12583 + Mcqs in Physics Page 207 McqOptions

10301.	Assertion : ac is more dangerous than dc Reason : Frequency of ac is dangerous for human body.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10302.	Assertion : Blue colour of sky appears due to scattering of blue colour. Reason : Blue colour has shortest wave length in visible spectrum. [AIIMS 2001]
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10303.	Beats are produced by two waves \[{{y}_{1}}=a\sin 1000\,\pi t,\] \[{{y}_{2}}=a\sin 998\pi t\] The number of beats heard/sec is [KCET 1998]
A.	0
B.	2
C.	1
D.	4
Answer» D. 4

Discussion

10304.	Maximum number of beats frequency heard by a human being is [RPMT 2000]
A.	10
B.	4
C.	20
D.	6
Answer» B. 4

Discussion

10305.	Assertion : The images formed by total internal reflections are much brighter than those formed by mirrors or lenses. Reason : There is no loss of intensity in total internal reflection.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10306.	The amount of work, which can be obtained by supplying 200 cal of heat, is [Pb. PET 2001, 03; BHU 2004]
A.	840 dyne
B.	840 W
C.	840 erg
D.	840 J
Answer» E.

Discussion

10307.	The resistance of a cell does not depend on [RPET 1996]
A.	Current drawn from the cell
B.	Temperature of electrolyte
C.	Concentration of electrolyte
D.	The e.m.f. of the cell
Answer» E.

Discussion

10308.	Assertion : When a magnetic dipole is placed in a non uniform magnetic field, only a torque acts on the dipole. Reason : Force would also acts on dipole if magnetic field were uniform.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

10309.	If \[\overrightarrow{A}=4\hat{i}-3\hat{j}\] and \[\overrightarrow{B}=6\hat{i}+8\hat{j}\] then magnitude and direction of \[\overrightarrow{A}\,+\overrightarrow{B}\] will be
A.	\[5,\,{{\tan }^{-1}}(3/4)\]
B.	\[5\sqrt{5},{{\tan }^{-1}}(1/2)\]
C.	\[10,\,{{\tan }^{-1}}(5)\]
D.	\[25,\,{{\tan }^{-1}}(3/4)\]
Answer» C. \[10,\,{{\tan }^{-1}}(5)\]

Discussion

10310.	Assertion : Mass is a measure of inertia of the body in linear motion. Reason : Greater the mass, greater is the force required to change its state of rest or of uniform motion.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10311.	In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.170 second. The frequency of the wave is [CBSE PMT 1998; AIIMS 2001; AFMC 2002; CPMT 2004]
A.	1.47 Hz
B.	0.36 Hz
C.	0.73 Hz
D.	2.94 Hz
Answer» B. 0.36 Hz

Discussion

10312.	The ratio of the speed of sound in nitrogen gas to that in helium gas, at 300 K is [IIT 1999]
A.	\[\sqrt{2/7}\]
B.	\[\sqrt{1/7}\]
C.	\[\sqrt{3}/5\]
D.	\[\sqrt{6}/5\]
Answer» D. \[\sqrt{6}/5\]

Discussion

10313.	The minimum audible wavelength at room temperature is about [AFMC 1996]
A.	0.2 Å
B.	5 Å
C.	5 cm to 2 metre
D.	20 mm
Answer» E.

Discussion

10314.	Assertion : A fluid flowing out of a small hole in a vessel apply a backward thrust on the vessel. Reason : According to equation of continuity, the product of area and velocity remain constant.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10315.	According to Bohr's theory the radius of electron in an orbit described by principal quantum number n and atomic number Z is proportional to [CPMT 1988]
A.	\[{{Z}^{2}}{{n}^{2}}\]
B.	\[\frac{{{Z}^{2}}}{{{n}^{2}}}\]
C.	\[\frac{{{Z}^{2}}}{n}\]
D.	\[\frac{{{n}^{2}}}{Z}\]
Answer» E.

Discussion

10316.	Assertion : The trajectory of projectile is quadratic in y and linear in x. Reason : y component of trajectory is independent of x-component.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

10317.	Assertion : A player lowers his hands while catching a cricket ball and suffers less reaction force. Reason : The time of catch increases when cricketer lowers its hand while catching a ball.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10318.	Two point charges \[+3\mu C\] and \[+8\mu C\] repel each other with a force of \[40N\]. If a charge of \[-5\mu C\]is added to each of them, then the force between them will become [SCRA 1998; JIPMER 2000]
A.	\[-10N\]
B.	\[+10N\]
C.	\[+20N\]
D.	\[-20N\]
Answer» B. \[+10N\]

Discussion

10319.	A cylindrical rod having temperature \[{{T}_{1}}\] and \[{{T}_{2}}\] at its ends. The rate of flow of heat is \[{{Q}_{1}}\]cal/sec. If all the linear dimensions are doubled keeping temperature constant then rate of flow of heat \[{{Q}_{2}}\]will be [CBSE PMT 2001]
A.	\[4{{Q}_{1}}\]
B.	\[2{{Q}_{1}}\]
C.	\[\frac{{{Q}_{1}}}{4}\]
D.	\[\frac{{{Q}_{1}}}{2}\]
Answer» C. \[\frac{{{Q}_{1}}}{4}\]

Discussion

10320.	The isothermal elasticity of a gas is equal to [CPMT 1981; MP PMT 2004]
A.	Density
B.	Volume
C.	Pressure
D.	Specific heat
Answer» D. Specific heat

Discussion

10321.	Assertion : When PN-junction is forward biased then motion of charge carriers at junction is due to diffusion. In reverse biasing. The cause of motion of charge is drifting. Reason : In the following circuit emitter is reverse biased and collector is forward biased.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10322.	Assertion : 29 is the equivalent decimal number of binary number 11101. Reason : (11101)2 = (1 ´ 24 + 1 ´ 23 + 1 ´ 22 + 0 ´ 21 + 1 ´ 20 )10 = (16 + 8 + 4 + 0 + 1)10 = (29)10
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10323.	Assertion : De-morgan's theorem \[\overline{A+B}=\bar{A}\cdot \bar{B}\] may be explained by the following circuit Reason : In the following circuit, for output inputs ABC are 101
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» D. If the assertion and reason both are false.

Discussion

10324.	If wavelength of a wave is \[\lambda =6000{AA}.\] Then wave number will be [MH CET 2002]
A.	\[166\times {{10}^{3}}\] m?1
B.	\[16.6\times {{10}^{-1}}\] m?1
C.	\[1.66\times {{10}^{6}}\] m?1
D.	\[1.66\times {{10}^{7}}\] m?1
Answer» D. \[1.66\times {{10}^{7}}\] m?1

Discussion

10325.	Find the frequency of minimum distance between compression & rarefaction of a wire. If the length of the wire is 1m & velocity of sound in air is 360 m/s [CPMT 2003]
A.	90 sec?1
B.	180s?1
C.	120 sec?1
D.	360 sec?1
Answer» B. 180s?1

Discussion

10326.	An ac supply gives 30 V r.m.s. which passes through a 10\[\Omega \] resistance. The power dissipated in it is [AMU (Med.) 2001]
A.	\[90\sqrt{2}\,W\]
B.	\[90\,W\]
C.	\[45\sqrt{2}\,W\]
D.	\[45\,W\]
Answer» C. \[45\sqrt{2}\,W\]

Discussion

10327.	Assertion : The tyres of aircraft's are slightly conducting. Reason : If a conductor is connected to ground, the extra charge induced on conductor will flow to ground.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10328.	When a dielectric material is introduced between the plates of a charges condenser, then electric field between the plates [Pb PMT 2004]
A.	Remain constant
B.	Decreases
C.	Increases
D.	First increases then decreases
Answer» C. Increases

Discussion

10329.	Assertion : The equation of motion can be applied only if acceleration is along the direction of velocity and is constant. Reason : If the acceleration of a body is constant then its motion is known as uniform motion.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

10330.	In an electron gun, the electrons are accelerated by the potential V. If e is the charge and m is the mass of an electron, then the maximum velocity of these electrons will be [MP PMT 1987, 96; BHU 1995; MNR 1998]
A.	\[\frac{2eV}{m}\]
B.	\[\sqrt{\frac{2eV}{m}}\]
C.	\[\sqrt{\frac{2m}{eV}}\]
D.	\[\frac{{{V}^{2}}}{2em}\]
Answer» C. \[\sqrt{\frac{2m}{eV}}\]

Discussion

10331.	Assertion : The radiation from the sun?s surface varies as the fourth power of its absolute temperature. Reason : The sun is not a black body. [AIIMS 1999]
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» D. If the assertion and reason both are false.

Discussion

10332.	Assertion : X-rays cannot be diffracted by means of grating. Reason : X-rays does not obey Bragg's law.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» D. If the assertion and reason both are false.

Discussion

10333.	Cathode rays and canal rays produced in a certain discharge tube are deflected in the same direction if [SCRA 1998]
A.	A magnetic field is applied normally
B.	An electric field is applied normally
C.	An electric field is applied tangentially
D.	A magnetic field is applied tangentially
Answer» B. An electric field is applied normally

Discussion

10334.	A slab consists of two parallel layers of copper and brass of the same thickness and having thermal conductivities in the ratio 1 : 4. If the free face of brass is at \[{{35}^{o}}C\] and that of copper at \[1:\sqrt{2.5}\], the temperature of interface is [IIT 1981; MP PMT 1987, 2001]
A.	80°C
B.	20°C
C.	60°C
D.	40°C
Answer» B. 20°C

Discussion

10335.	Assertion : In a simple battery circuit the point of lowest potential is positive terminal of the battery Reason : The current flows towards the point of the higher potential as it flows in such a circuit from the negative to the positive terminal. [AIIMS 2002]
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

10336.	Two straight horizontal parallel wires are carrying the same current in the same direction, d is the distance between the wires. You are provided with a small freely suspended magnetic needle. At which of the following positions will the orientation of the needle be independent of the magnitude of the current in the wires [NCERT 1983]
A.	At a distance \[d/2\] from any of the wires
B.	At a distance \[d/2\] from any of the wires in the horizontal plane
C.	Anywhere on the circumference of a vertical circle of radius d and centre halfway between the wires
D.	At points halfway between the wires in the horizontal plane
Answer» E.

Discussion

10337.	By exerting a certain amount of pressure on an ice block, you [JIPMER 1997]
A.	Lower its melting point
B.	Make it melt at 0°C only
C.	Make it melt at a faster rate
D.	Raise its melting point
Answer» B. Make it melt at 0°C only

Discussion

10338.	Assertion : The heat supplied to a system is always equal to the increase in its internal energy. Reason : When a system changes from one thermal equilibrium to another, some heat is absorbed by it.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

10339.	In the lowest energy level of hydrogen atom, the electron has the angular momentum [MP PET 1997; BCECE 2003]
A.	\[\pi /h\]
B.	\[h/\pi \]
C.	\[h/2\pi \]
D.	\[2\pi /h\]
Answer» D. \[2\pi /h\]

Discussion

10340.	The speed of an electron having a wavelength of \[{{10}^{-10}}\,m\] is [AIIMS 2002]
A.	\[7.25\times {{10}^{6}}\,m/s\]
B.	\[6.26\times {{10}^{6}}\,m/s\]
C.	\[5.25\times {{10}^{6}}\,m/s\]
D.	\[4.24\times {{10}^{6}}\,m/s\]
Answer» B. \[6.26\times {{10}^{6}}\,m/s\]

Discussion

10341.	Assertion : In javelin throw, the athlete throws the projectile at an angle slightly more than 45°. Reason : The maximum range does not depends upon angle of projection.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

10342.	Assertion : The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased. Reason : On increasing temperature, conductivity of metallic wire decreases.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. If assertion is true but reason is false.

Discussion

10343.	Assertion : When a body is subjected to a uniform acceleration, it always move in a straight line. Reason : Straight line motion is the natural tendency of the body.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» F.

Discussion

10344.	One mole of an ideal gas at an initial temperature of T K does 6 R joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, the final temperature of gas will be [CBSE PMT 2004]
A.	\[(T+2.4)\,K\]
B.	\[(T-2.4)\,K\]
C.	\[(T+4)\,K\]
D.	\[(T-4)\,K\]
Answer» E.

Discussion

10345.	Assertion : Two thin blankets put together are warmer than a single blanket of double the thickness. Reason : Thickness increases because of air layer enclosed between the two blankets.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» D. If the assertion and reason both are false.

Discussion

10346.	The current flowing in a copper voltameter is 1.6 A. The number of \[C{{u}^{++}}\] ions deposited at the cathode per minute are [MP PMT 1994; MP PET 2000]
A.	\[1.5\times {{10}^{20}}\]
B.	\[3\times {{10}^{20}}\]
C.	\[6\times {{10}^{20}}\]
D.	\[1\times {{10}^{19}}\]
Answer» C. \[6\times {{10}^{20}}\]

Discussion

10347.	Assertion : It is not possible to have interference between the waves produced by two violins. Reason : For interference of two waves the phase difference between the waves must remain constant.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10348.	In adiabatic expansion of a gas [BCECE 2001; MP PET 2003]
A.	Its pressure increases
B.	Its temperature falls
C.	Its density increases
D.	Its thermal energy increases
Answer» C. Its density increases

Discussion

10349.	Assertion : If the speed of a body is constant, the body cannot have a path other than a circular or straight line path. Reason : It is not possible for a body to have a constant speed in an accelerated motion.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» E. If assertion is false but reason is true.

Discussion

10350.	Assertion : If earth were a hollow sphere, gravitational field intensity at any point inside the earth would be zero. Reason : Net force on a body inside the sphere is zero.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	If assertion is true but reason is false.
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

Explore topic-wise MCQs in Joint Entrance Exam - Main (JEE Main).

Assertion : ac is more dangerous than dc Reason : Frequency of ac is dangerous for human body.

Assertion : Blue colour of sky appears due to scattering of blue colour. Reason : Blue colour has shortest wave length in visible spectrum. [AIIMS 2001]

Beats are produced by two waves \[{{y}_{1}}=a\sin 1000\,\pi t,\] \[{{y}_{2}}=a\sin 998\pi t\] The number of beats heard/sec is [KCET 1998]

Maximum number of beats frequency heard by a human being is [RPMT 2000]

Assertion : The images formed by total internal reflections are much brighter than those formed by mirrors or lenses. Reason : There is no loss of intensity in total internal reflection.

The amount of work, which can be obtained by supplying 200 cal of heat, is [Pb. PET 2001, 03; BHU 2004]

The resistance of a cell does not depend on [RPET 1996]

Assertion : When a magnetic dipole is placed in a non uniform magnetic field, only a torque acts on the dipole. Reason : Force would also acts on dipole if magnetic field were uniform.

If \[\overrightarrow{A}=4\hat{i}-3\hat{j}\] and \[\overrightarrow{B}=6\hat{i}+8\hat{j}\] then magnitude and direction of \[\overrightarrow{A}\,+\overrightarrow{B}\] will be

Assertion : Mass is a measure of inertia of the body in linear motion. Reason : Greater the mass, greater is the force required to change its state of rest or of uniform motion.

In a sinusoidal wave, the time required for a particular point to move from maximum displacement to zero displacement is 0.170 second. The frequency of the wave is [CBSE PMT 1998; AIIMS 2001; AFMC 2002; CPMT 2004]

The ratio of the speed of sound in nitrogen gas to that in helium gas, at 300 K is [IIT 1999]

The minimum audible wavelength at room temperature is about [AFMC 1996]

Assertion : A fluid flowing out of a small hole in a vessel apply a backward thrust on the vessel. Reason : According to equation of continuity, the product of area and velocity remain constant.

According to Bohr's theory the radius of electron in an orbit described by principal quantum number n and atomic number Z is proportional to [CPMT 1988]

Assertion : The trajectory of projectile is quadratic in y and linear in x. Reason : y component of trajectory is independent of x-component.

Assertion : A player lowers his hands while catching a cricket ball and suffers less reaction force. Reason : The time of catch increases when cricketer lowers its hand while catching a ball.

Two point charges \[+3\mu C\] and \[+8\mu C\] repel each other with a force of \[40N\]. If a charge of \[-5\mu C\]is added to each of them, then the force between them will become [SCRA 1998; JIPMER 2000]

A cylindrical rod having temperature \[{{T}_{1}}\] and \[{{T}_{2}}\] at its ends. The rate of flow of heat is \[{{Q}_{1}}\]cal/sec. If all the linear dimensions are doubled keeping temperature constant then rate of flow of heat \[{{Q}_{2}}\]will be [CBSE PMT 2001]

The isothermal elasticity of a gas is equal to [CPMT 1981; MP PMT 2004]

Assertion : When PN-junction is forward biased then motion of charge carriers at junction is due to diffusion. In reverse biasing. The cause of motion of charge is drifting. Reason : In the following circuit emitter is reverse biased and collector is forward biased.

Assertion : 29 is the equivalent decimal number of binary number 11101. Reason : (11101)2 = (1 ´ 24 + 1 ´ 23 + 1 ´ 22 + 0 ´ 21 + 1 ´ 20 )10 = (16 + 8 + 4 + 0 + 1)10 = (29)10

Assertion : De-morgan's theorem \[\overline{A+B}=\bar{A}\cdot \bar{B}\] may be explained by the following circuit Reason : In the following circuit, for output inputs ABC are 101

If wavelength of a wave is \[\lambda =6000{AA}.\] Then wave number will be [MH CET 2002]

Find the frequency of minimum distance between compression & rarefaction of a wire. If the length of the wire is 1m & velocity of sound in air is 360 m/s [CPMT 2003]

An ac supply gives 30 V r.m.s. which passes through a 10\[\Omega \] resistance. The power dissipated in it is [AMU (Med.) 2001]

Assertion : The tyres of aircraft's are slightly conducting. Reason : If a conductor is connected to ground, the extra charge induced on conductor will flow to ground.

When a dielectric material is introduced between the plates of a charges condenser, then electric field between the plates [Pb PMT 2004]

Assertion : The equation of motion can be applied only if acceleration is along the direction of velocity and is constant. Reason : If the acceleration of a body is constant then its motion is known as uniform motion.

In an electron gun, the electrons are accelerated by the potential V. If e is the charge and m is the mass of an electron, then the maximum velocity of these electrons will be [MP PMT 1987, 96; BHU 1995; MNR 1998]

Assertion : The radiation from the sun?s surface varies as the fourth power of its absolute temperature. Reason : The sun is not a black body. [AIIMS 1999]

Assertion : X-rays cannot be diffracted by means of grating. Reason : X-rays does not obey Bragg's law.

Cathode rays and canal rays produced in a certain discharge tube are deflected in the same direction if [SCRA 1998]

A slab consists of two parallel layers of copper and brass of the same thickness and having thermal conductivities in the ratio 1 : 4. If the free face of brass is at \[{{35}^{o}}C\] and that of copper at \[1:\sqrt{2.5}\], the temperature of interface is [IIT 1981; MP PMT 1987, 2001]

Assertion : In a simple battery circuit the point of lowest potential is positive terminal of the battery Reason : The current flows towards the point of the higher potential as it flows in such a circuit from the negative to the positive terminal. [AIIMS 2002]

By exerting a certain amount of pressure on an ice block, you [JIPMER 1997]

Assertion : The heat supplied to a system is always equal to the increase in its internal energy. Reason : When a system changes from one thermal equilibrium to another, some heat is absorbed by it.

In the lowest energy level of hydrogen atom, the electron has the angular momentum [MP PET 1997; BCECE 2003]

The speed of an electron having a wavelength of \[{{10}^{-10}}\,m\] is [AIIMS 2002]

Assertion : In javelin throw, the athlete throws the projectile at an angle slightly more than 45°. Reason : The maximum range does not depends upon angle of projection.

Assertion : The drift velocity of electrons in a metallic wire will decrease, if the temperature of the wire is increased. Reason : On increasing temperature, conductivity of metallic wire decreases.

Assertion : When a body is subjected to a uniform acceleration, it always move in a straight line. Reason : Straight line motion is the natural tendency of the body.

One mole of an ideal gas at an initial temperature of T K does 6 R joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, the final temperature of gas will be [CBSE PMT 2004]

Assertion : Two thin blankets put together are warmer than a single blanket of double the thickness. Reason : Thickness increases because of air layer enclosed between the two blankets.

The current flowing in a copper voltameter is 1.6 A. The number of \[C{{u}^{++}}\] ions deposited at the cathode per minute are [MP PMT 1994; MP PET 2000]

Assertion : It is not possible to have interference between the waves produced by two violins. Reason : For interference of two waves the phase difference between the waves must remain constant.

In adiabatic expansion of a gas [BCECE 2001; MP PET 2003]

Assertion : If the speed of a body is constant, the body cannot have a path other than a circular or straight line path. Reason : It is not possible for a body to have a constant speed in an accelerated motion.

Assertion : If earth were a hollow sphere, gravitational field intensity at any point inside the earth would be zero. Reason : Net force on a body inside the sphere is zero.