12583 + Mcqs in Physics Page 189 McqOptions

9401.	A capacitor of capacitance \[6\mu \,F\] is charged upto 100 volt. The energy stored in the capacitor is [BHU 2003; CPMT 2004; MP PMT 2005]
A.	0.6 Joule
B.	0.06 Joule
C.	0.03 Joule
D.	0.3 Joule
Answer» D. 0.3 Joule

Discussion

9402.	An ice cream has a marked value of 700 kcal. How many kilowatt- hour of energy will it deliver to the body as it is digested [AMU (Med.) 2000]
A.	\[0.81\,kWh\]
B.	\[0.90\,kWh\]
C.	\[1.11kWh\]
D.	\[0.71\,kWh\]
Answer» B. \[0.90\,kWh\]

Discussion

9403.	Ampere hour is the unit of [Orissa JEE 2005]
A.	Quantity of charge
B.	Potential
C.	Energy
D.	Current
Answer» B. Potential

Discussion

9404.	The depth d at which the value of acceleration due to gravity becomes \[\frac{1}{n}\] times the value at the surface, is [R = radius of the earth] [MP PMT 1999; Kerala PMT 2005]
A.	\[\frac{R}{n}\]
B.	\[R\,\left( \frac{n-1}{n} \right)\]
C.	\[\frac{R}{{{n}^{2}}}\]
D.	\[R\,\left( \frac{n}{n+1} \right)\]
Answer» C. \[\frac{R}{{{n}^{2}}}\]

Discussion

9405.	Indicate which one of the following system is digital
A.	Pulse position modulation
B.	Pulse code modulation
C.	Pulse width modulation
D.	Pulse amplitude modulation
Answer» C. Pulse width modulation

Discussion

9406.	Charge on \[\alpha \]-particle is [MH CET 2000]
A.	\[4.8\times {{10}^{-19}}C\]
B.	\[1.6\times {{10}^{-19}}C\]
C.	\[3.2\times {{10}^{-19}}C\]
D.	\[6.4\times {{10}^{-19}}C\]
Answer» D. \[6.4\times {{10}^{-19}}C\]

Discussion

9407.	Assertion : No force is required by the body to remain in any state. Reason : In uniform linear motion, acceleration has a finite value.
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

9408.	Assertion : An alternating current does not show any magnetic effect. Reason : Alternating current varies with time.
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

9409.	What will be the wave velocity, if the radar gives 54 waves per min and wavelength of the given wave is 10 m [RPET 2000]
A.	4 m/sec
B.	6 m/sec
C.	9 m/sec
D.	5 m/sec
Answer» D. 5 m/sec

Discussion

9410.	Sound velocity is maximum in [Pb. CET 2000; RPMT 2000]
A.	\[{{H}_{2}}\]
B.	\[{{N}_{2}}\]
C.	\[He\]
D.	\[{{O}_{2}}\]
Answer» B. \[{{N}_{2}}\]

Discussion

9411.	Assertion : A body falling freely may do so with constant velocity. Reason : The body falls freely, when acceleration of a body is equal to acceleration due to gravity.
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

9412.	The frequency of a tunning fork is 384 per second and velocity of sound in air is 352 m/s. How far the sound has traversed while fork completes 36 vibration [KCET 2001]
A.	3 m
B.	13 m
C.	23 m
D.	33 m
Answer» E.

Discussion

9413.	Assertion : The mass of a nucleus can be either less than or more than the sum of the masses of nucleons present in it. Reason : The whole mass of the atom is considered in the nucleus.
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

9414.	Consider an electron in the nth orbit of a hydrogen atom in the Bohr model. The circumference of the orbit can be expressed in terms of the de Broglie wavelength \[\lambda \]of that electron as [CBSE PMT 1990]
A.	\[(0.259)\ n\lambda \]
B.	\[\sqrt{n}\lambda \]
C.	\[(13.6)\ \lambda \]
D.	\[n\lambda \]
Answer» E.

Discussion

9415.	Minimum energy required to takeout the only one electron from ground state of \[H{{e}^{+}}\] is [CPMT 2002]
A.	13.6 eV
B.	54.4 eV
C.	27.2 eV
D.	6.8 eV
Answer» C. 27.2 eV

Discussion

9416.	There are two identical vessels filled with equal amounts of ice. The vessels are of different metals., If the ice melts in the two vessels in 20 and 35 minutes respectively, the ratio of the coefficients of thermal conductivity of the two metals is [AFMC 1998; MP PET 2001]
A.	4 : 7
B.	7 : 4
C.	16 :49
D.	49 : 16
Answer» C. 16 :49

Discussion

9417.	If the value of ?g? acceleration due to gravity, at earth surface is \[10\,m/{{s}^{2}}\], its value in \[m/{{s}^{2}}\] at the centre of the earth, which is assumed to be a sphere of radius ?R? metre and uniform mass density is [AIIMS 2002]
A.	5
B.	10/R
C.	10/2R
D.	Zero
Answer» E.

Discussion

9418.	Assertion : A room can be cooled by opening the door of a refrigerator in a closed room. Reason : Heat flows from lower temperature (refrigerator) to higher temperature (room).
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

9419.	Two walls of thicknesses d1 and d2 and thermal conductivities k1 and k2 are in contact. In the steady state, if the temperatures at the outer surfaces are \[{{T}_{1}}\] and \[{{T}_{2}}\], the temperature at the common wall is [MP PMT 1990; CBSE PMT 1999]
A.	\[\frac{{{k}_{1}}{{T}_{1}}{{d}_{2}}+{{k}_{2}}{{T}_{2}}{{d}_{1}}}{{{k}_{1}}{{d}_{2}}+{{k}_{2}}{{d}_{1}}}\]
B.	\[\frac{{{k}_{1}}{{T}_{1}}+{{k}_{2}}{{d}_{2}}}{{{d}_{1}}+{{d}_{2}}}\]
C.	\[\left( \frac{{{k}_{1}}{{d}_{1}}+{{k}_{2}}{{d}_{2}}}{{{T}_{1}}+{{T}_{2}}} \right){{T}_{1}}{{T}_{2}}\]
D.	\[\frac{{{k}_{1}}{{d}_{1}}{{T}_{1}}+{{k}_{2}}{{d}_{2}}{{T}_{2}}}{{{k}_{1}}{{d}_{1}}+{{k}_{2}}{{d}_{2}}}\]
Answer» B. \[\frac{{{k}_{1}}{{T}_{1}}+{{k}_{2}}{{d}_{2}}}{{{d}_{1}}+{{d}_{2}}}\]

Discussion

9420.	One metallic sphere \[A\] is given positive charge whereas another identical metallic sphere \[B\] of exactly same mass as of \[A\]is given equal amount of negative charge. Then [AMU 1995; RPET 2000; CPMT 2000]
A.	Mass of \[A\] and mass of \[B\] still remain equal
B.	Mass of \[A\] increases
C.	Mass of \[B\] decreases
D.	Mass of \[B\] increases
Answer» E.

Discussion

9421.	In the three states of matter, the elastic coefficient can be
A.	Young's modulus
B.	Coefficient of volume elasticity
C.	Modulus of rigidity
D.	Poisson's ratio
Answer» C. Modulus of rigidity

Discussion

9422.	In a discharge tube at 0.02 mm, there is a formation of [CBSE PMT 1996]
A.	FDS
B.	CDS
C.	Both space
D.	None of these
Answer» C. Both space

Discussion

9423.	If the wavelength of the first line of the Balmer series of hydrogen is\[6561\ {AA}\], the wavelength of the second line of the series should be [CPMT 1984; DPMT 2004]
A.	\[13122\ {AA}\]
B.	\[3280\ {AA}\]
C.	\[4860\ {AA}\]
D.	\[2187\ {AA}\]
Answer» D. \[2187\ {AA}\]

Discussion

9424.	Assertion : The induced emf in a conducting loop of wire will be non zero when it rotates in a uniform magnetic field. Reason : The emf is induced due to change in magnetic flux.
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

9425.	Read the assertion and reason carefully to mark the correct option out of the options given below: Assertion : On a rainy day, it is difficult to drive a car or bus at high speed. Reason : The value of coefficient of friction is lowered due to wetting of the surface.
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

9426.	The pressure applied from all directions on a cube is P. How much its temperature should be raised to maintain the original volume ? The volume elasticity of the cube is \[\beta \] and the coefficient of volume expansion is \[\alpha \]
A.	\[\frac{P}{\alpha \beta }\]
B.	\[\frac{P\alpha }{\beta }\]
C.	\[\frac{P\beta }{\alpha }\]
D.	\[\frac{\alpha \beta }{P}\]
Answer» B. \[\frac{P\alpha }{\beta }\]

Discussion

9427.	Assertion : Base in a transistor is made very thin as compared to collector and emitter regions. Reason : Due to thin base power gain and voltage gain is obtained by a transistor.
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

9428.	Assertion : NAND or NOR gates are called digital building blocks. Reason : The repeated use of NAND (or NOR) gates can produce all the basic or complicated gates.
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

9429.	Assertion : At 0 K Germanium is a superconductor. Reason : At 0 K Germanium offers zero resistance.
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

9430.	Positive rays was discovered by [RPMT 1998]
A.	Thomson
B.	Goldstem
C.	W. Crookes
D.	Rutherford
Answer» B. Goldstem

Discussion

9431.	Order of q/m ratio of proton, \[\alpha \]-particle and electron is [AFMC 2004]
A.	\[e>p>\alpha \]
B.	\[p>\alpha >e\]
C.	\[e>\alpha >p\]
D.	None of these
Answer» B. \[p>\alpha >e\]

Discussion

9432.	Assertion : According to classical theory, the proposed path of an electron in Rutherford atom model will be parabolic. Reason : According to electromagnetic theory an accelerated particle continuously emits radiation.
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

9433.	Assertion : The surface charge densities of two spherical conductors of different radii are equal. Then the electric field intensities near their surface are also equal. Reason : Surface charge density is equal to charge per unit area.
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

9434.	Assertion : When a vehicle takes a turn on the road, it travels along a nearly circular path. Reason : In circular motion, velocity of vehicle remains same.
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

9435.	According to the experiment of Ingen Hausz the relation between the thermal conductivity of a metal rod is K and the length of the rod whenever the wax melts is [UPSEAT 1999]
A.	K/l = constant
B.	\[{{K}^{2}}/l\]= constant
C.	\[K/{{l}^{2}}\]= constant
D.	\[Kl\]= constant
Answer» D. \[Kl\]= constant

Discussion

9436.	Two forces, \[{{F}_{1}}\] and \[{{F}_{2}}\] are acting on a body. One force is double that of the other force and the resultant is equal to the greater force. Then the angle between the two forces is
A.	\[{{\cos }^{-1}}(1/2)\]
B.	\[{{\cos }^{-1}}(-1/2)\]
C.	\[{{\cos }^{-1}}(-1/4)\]
D.	\[{{\cos }^{-1}}(1/4)\]
Answer» D. \[{{\cos }^{-1}}(1/4)\]

Discussion

9437.	Assertion : To hear distinct beats, difference in frequencies of two sources should be less than 10. Reason : More the number of beats per sec more difficult to hear them.
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

9438.	Assertion : Sound produced by an open organ pipe is richer than the sound produced by a closed organ pipe. Reason : Outside air can enter the pipe from both ends, in case of open organ pipe.
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

9439.	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

9440.	Assertion : On a rainy day sound travel slower than on a dry day. Reason : When moisture is present in air the density of air increases.
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

9441.	The velocity of sound is vs in air. If the density of air is increased to 4 times, then the new velocity of sound will be [BHU 2003]
A.	\[\frac{{{v}_{s}}}{2}\]
B.	\[\frac{{{v}_{s}}}{12}\]
C.	\[12{{v}_{s}}\]
D.	\[\frac{3}{2}v_{s}^{2}\]
Answer» B. \[\frac{{{v}_{s}}}{12}\]

Discussion

9442.	In the above question, the magnetic induction at O due to the whole length of the conductor is [MP PMT/PET 1998; RPET 2002]
A.	\[\frac{{{\mu }_{0}}i}{r}\]
B.	\[\frac{{{\mu }_{0}}i}{2r}\]
C.	\[\frac{{{\mu }_{0}}i}{4r}\]
D.	Zero
Answer» D. Zero

Discussion

9443.	Assertion : Velocity of particles, while crossing mean position (in stationary waves) varies from maximum at antinodes to zero at nodes. Reason : Amplitude of vibration at antinodes is maximum and at nodes, the amplitude is zero, And all particles between two successive nodes cross the mean position together.
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

9444.	Assertion : Where two vibrating tuning forks having frequencies 256 Hz and 512 Hz are held near each other, beats cannot be heard. Reason : The principle of superposition is valid only if the frequencies of the oscillators are nearly equal.
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

9445.	Assertion : The fundamental frequency of an open organ pipe increases as the temperature is increased. Reason : As the temperature increases, the velocity of sound increases more rapidly than length of the pipe.
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

9446.	Assertion : Aeroplanes always fly at low altitudes. Reason : According to Newton?s third law of motion, for every action there is an equal and opposite reaction.
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

9447.	An electron has a mass of \[9.1\times {{10}^{-31}}kg\]. It revolves round the nucleus in a circular orbit of radius \[0.529\times {{10}^{-10}}metre\]at a speed of \[2.2\times {{10}^{6}}m/s\]. The magnitude of its linear momentum in this motion is [AFMC 1988]
A.	\[1.1\times {{10}^{-34}}kg-m/s\]
B.	\[2.0\times {{10}^{-24}}kg-m/s\]
C.	\[4.0\times {{10}^{-24}}kg-m/s\]
D.	\[4.0\times {{10}^{-31}}kg-m/s\]
Answer» C. \[4.0\times {{10}^{-24}}kg-m/s\]

Discussion

9448.	The impedance of a circuit consists of 3 ohm resistance and 4 ohm reactance. The power factor of the circuit is [MP PMT 1994]
A.	0.4
B.	0.6
C.	0.8
D.	1.0
Answer» C. 0.8

Discussion

9449.	An electric motor operating on a 60 V dc supply draws a current of 10 A. If the efficiency of the motor is 50%, the resistance of its winding is [AMU (Engg.) 2001]
A.	\[3\Omega \]
B.	\[6\Omega \]
C.	\[15\Omega \]
D.	\[30\Omega \]
Answer» B. \[6\Omega \]

Discussion

9450.	Assertion : A reference frame attached to earth is an inertial frame of reference. Reason : The reference frame which has zero acceleration is called a non-inertial frame of reference.
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

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

A capacitor of capacitance \[6\mu \,F\] is charged upto 100 volt. The energy stored in the capacitor is [BHU 2003; CPMT 2004; MP PMT 2005]

An ice cream has a marked value of 700 kcal. How many kilowatt- hour of energy will it deliver to the body as it is digested [AMU (Med.) 2000]

Ampere hour is the unit of [Orissa JEE 2005]

The depth d at which the value of acceleration due to gravity becomes \[\frac{1}{n}\] times the value at the surface, is [R = radius of the earth] [MP PMT 1999; Kerala PMT 2005]

Indicate which one of the following system is digital

Charge on \[\alpha \]-particle is [MH CET 2000]

Assertion : No force is required by the body to remain in any state. Reason : In uniform linear motion, acceleration has a finite value.

Assertion : An alternating current does not show any magnetic effect. Reason : Alternating current varies with time.

What will be the wave velocity, if the radar gives 54 waves per min and wavelength of the given wave is 10 m [RPET 2000]

Sound velocity is maximum in [Pb. CET 2000; RPMT 2000]

Assertion : A body falling freely may do so with constant velocity. Reason : The body falls freely, when acceleration of a body is equal to acceleration due to gravity.

The frequency of a tunning fork is 384 per second and velocity of sound in air is 352 m/s. How far the sound has traversed while fork completes 36 vibration [KCET 2001]

Assertion : The mass of a nucleus can be either less than or more than the sum of the masses of nucleons present in it. Reason : The whole mass of the atom is considered in the nucleus.

Consider an electron in the nth orbit of a hydrogen atom in the Bohr model. The circumference of the orbit can be expressed in terms of the de Broglie wavelength \[\lambda \]of that electron as [CBSE PMT 1990]

Minimum energy required to takeout the only one electron from ground state of \[H{{e}^{+}}\] is [CPMT 2002]

There are two identical vessels filled with equal amounts of ice. The vessels are of different metals., If the ice melts in the two vessels in 20 and 35 minutes respectively, the ratio of the coefficients of thermal conductivity of the two metals is [AFMC 1998; MP PET 2001]

If the value of ?g? acceleration due to gravity, at earth surface is \[10\,m/{{s}^{2}}\], its value in \[m/{{s}^{2}}\] at the centre of the earth, which is assumed to be a sphere of radius ?R? metre and uniform mass density is [AIIMS 2002]

Assertion : A room can be cooled by opening the door of a refrigerator in a closed room. Reason : Heat flows from lower temperature (refrigerator) to higher temperature (room).

Two walls of thicknesses d1 and d2 and thermal conductivities k1 and k­2 are in contact. In the steady state, if the temperatures at the outer surfaces are \[{{T}_{1}}\] and \[{{T}_{2}}\], the temperature at the common wall is [MP PMT 1990; CBSE PMT 1999]

One metallic sphere \[A\] is given positive charge whereas another identical metallic sphere \[B\] of exactly same mass as of \[A\]is given equal amount of negative charge. Then [AMU 1995; RPET 2000; CPMT 2000]

In the three states of matter, the elastic coefficient can be

In a discharge tube at 0.02 mm, there is a formation of [CBSE PMT 1996]

If the wavelength of the first line of the Balmer series of hydrogen is\[6561\ {AA}\], the wavelength of the second line of the series should be [CPMT 1984; DPMT 2004]

Assertion : The induced emf in a conducting loop of wire will be non zero when it rotates in a uniform magnetic field. Reason : The emf is induced due to change in magnetic flux.

Read the assertion and reason carefully to mark the correct option out of the options given below: Assertion : On a rainy day, it is difficult to drive a car or bus at high speed. Reason : The value of coefficient of friction is lowered due to wetting of the surface.

The pressure applied from all directions on a cube is P. How much its temperature should be raised to maintain the original volume ? The volume elasticity of the cube is \[\beta \] and the coefficient of volume expansion is \[\alpha \]

Assertion : Base in a transistor is made very thin as compared to collector and emitter regions. Reason : Due to thin base power gain and voltage gain is obtained by a transistor.

Assertion : NAND or NOR gates are called digital building blocks. Reason : The repeated use of NAND (or NOR) gates can produce all the basic or complicated gates.

Assertion : At 0 K Germanium is a superconductor. Reason : At 0 K Germanium offers zero resistance.

Positive rays was discovered by [RPMT 1998]

Order of q/m ratio of proton, \[\alpha \]-particle and electron is [AFMC 2004]

Assertion : According to classical theory, the proposed path of an electron in Rutherford atom model will be parabolic. Reason : According to electromagnetic theory an accelerated particle continuously emits radiation.

Assertion : The surface charge densities of two spherical conductors of different radii are equal. Then the electric field intensities near their surface are also equal. Reason : Surface charge density is equal to charge per unit area.

Assertion : When a vehicle takes a turn on the road, it travels along a nearly circular path. Reason : In circular motion, velocity of vehicle remains same.

According to the experiment of Ingen Hausz the relation between the thermal conductivity of a metal rod is K and the length of the rod whenever the wax melts is [UPSEAT 1999]

Two forces, \[{{F}_{1}}\] and \[{{F}_{2}}\] are acting on a body. One force is double that of the other force and the resultant is equal to the greater force. Then the angle between the two forces is

Assertion : To hear distinct beats, difference in frequencies of two sources should be less than 10. Reason : More the number of beats per sec more difficult to hear them.

Assertion : Sound produced by an open organ pipe is richer than the sound produced by a closed organ pipe. Reason : Outside air can enter the pipe from both ends, in case of open organ pipe.

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]

Assertion : On a rainy day sound travel slower than on a dry day. Reason : When moisture is present in air the density of air increases.

The velocity of sound is vs in air. If the density of air is increased to 4 times, then the new velocity of sound will be [BHU 2003]

In the above question, the magnetic induction at O due to the whole length of the conductor is [MP PMT/PET 1998; RPET 2002]

Assertion : Where two vibrating tuning forks having frequencies 256 Hz and 512 Hz are held near each other, beats cannot be heard. Reason : The principle of superposition is valid only if the frequencies of the oscillators are nearly equal.

Assertion : The fundamental frequency of an open organ pipe increases as the temperature is increased. Reason : As the temperature increases, the velocity of sound increases more rapidly than length of the pipe.

Assertion : Aeroplanes always fly at low altitudes. Reason : According to Newton?s third law of motion, for every action there is an equal and opposite reaction.

An electron has a mass of \[9.1\times {{10}^{-31}}kg\]. It revolves round the nucleus in a circular orbit of radius \[0.529\times {{10}^{-10}}metre\]at a speed of \[2.2\times {{10}^{6}}m/s\]. The magnitude of its linear momentum in this motion is [AFMC 1988]

The impedance of a circuit consists of 3 ohm resistance and 4 ohm reactance. The power factor of the circuit is [MP PMT 1994]

An electric motor operating on a 60 V dc supply draws a current of 10 A. If the efficiency of the motor is 50%, the resistance of its winding is [AMU (Engg.) 2001]

Assertion : A reference frame attached to earth is an inertial frame of reference. Reason : The reference frame which has zero acceleration is called a non-inertial frame of reference.

Two walls of thicknesses d1 and d2 and thermal conductivities k1 and k2 are in contact. In the steady state, if the temperatures at the outer surfaces are \[{{T}_{1}}\] and \[{{T}_{2}}\], the temperature at the common wall is [MP PMT 1990; CBSE PMT 1999]