12583 + Mcqs in Physics Page 215 McqOptions

10701.	Assertion : A transformer cannot work on dc supply. Reason : dc changes neither in magnitude nor in direction.
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

10702.	A polyatomic gas \[\left( \gamma =\frac{4}{3} \right)\] is compressed to \[\frac{1}{8}\] of its volume adiabatically. If its initial pressure is \[{{P}_{o}}\], its new pressure will be [MP PET 1994; BHU 1995]
A.	\[8{{P}_{o}}\]
B.	\[16{{P}_{0}}\]
C.	\[6{{P}_{o}}\]
D.	\[2{{P}_{o}}\]
Answer» C. \[6{{P}_{o}}\]

Discussion

10703.	Assertion : The resolving power of an electron microscope is higher than that of an optical microscope. Reason : The wavelength of electron is more than the wavelength of visible light.
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

10704.	Assertion : Although the surfaces of a goggle lens are curved, it does not have any power. Reason : In case of goggles, both the curved surfaces have equal radii of curvature.
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

10705.	64 small drops of mercury, each of radius r and charge q coalesce to form a big drop. The ratio of the surface density of charge of each small drop with that of the big drop is [KCET 2002]
A.	1 : 64
B.	64 : 1
C.	4 : 1
D.	1 : 4
Answer» E.

Discussion

10706.	Assertion : If the angles of the base of the prism are equal, then in the position of minimum deviation, the refracted ray will pass parallel to the base of prism. Reason : In the case of minimum deviation, the angle of incidence is equal to the angle of emergence.
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

10707.	Assertion : A needle placed carefully on the surface of water may float, whereas a ball of the same material will always sink. Reason : The buoyancy of an object depends both on the material and shape of the object.
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

10708.	The current in series LCR circuit will be maximum when w is [Kerala PMT 2004]
A.	As large as possible
B.	Equal o natural frequency of LCR system
C.	\[\sqrt{LC}\]
D.	\[\sqrt{1/LC}\]
Answer» E.

Discussion

10709.	Assertion : The 200 W bulbs glows with more brightness then 100 W bulbs. Reason : A 100 W bulb has more resistance than a 200 W bulb.
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

10710.	Assertion : Machine parts are jammed in winter. Reason : The viscosity of lubricant used in machine parts increase at low temperature.
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

10711.	Reactance of a capacitor of capacitance \[C\mu F\] for ac frequency \[\frac{400}{\pi }\] Hz is \[25\Omega \]. The value C is [MH CET 2002]
A.	\[50\mu F\]
B.	\[25\mu F\]
C.	\[100\mu F\]
D.	\[75\mu F\]
Answer» B. \[25\mu F\]

Discussion

10712.	Assertion : Position-time graph of a stationary object is a straight line parallel to time axis. Reason : For a stationary object, position does not change 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» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

Discussion

10713.	If the diameter of a capillary tube is doubled, then the height of the liquid that will rise is [CPMT 1997]
A.	Twice
B.	Half
C.	Same as earlier
D.	None of these
Answer» C. Same as earlier

Discussion

10714.	Assertion : Linear momentum of a body changes even when it is moving uniformly in a circle. Reason : In uniform circular motion 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» D. If the assertion and reason both are false.

Discussion

10715.	Eddy currents are produced when [CBSE PMT 1993; AFMC 2002]
A.	A metal is kept in varying magnetic field
B.	A metal is kept in the steady magnetic field
C.	A circular coil is placed in a magnetic field
D.	Through a circular coil, current is passed
Answer» B. A metal is kept in the steady magnetic field

Discussion

10716.	A liquid wets a solid completely. The meniscus of the liquid in a sufficiently long tube is [Kerala (Engg.) 2002]
A.	Flat
B.	Concave
C.	Convex
D.	Cylindrical
Answer» C. Convex

Discussion

10717.	A charge of \[40\mu \,C\] is given to a capacitor having capacitance \[C=10\mu \,F\]. The stored energy in ergs is [CPMT 2002]
A.	\[80\times {{10}^{-6}}\]
B.	800
C.	80
D.	8000
Answer» C. 80

Discussion

10718.	In Bainbridge mass spectrograph a potential difference of 1000 V is applied between two plates distant 1 cm apart and magnetic field in B = 1T. The velocity of undeflected positive ions in m/s from the velocity selector is [RPMT 1998]
A.	\[{{10}^{7}}m/s\]
B.	\[{{10}^{4}}m/s\]
C.	\[{{10}^{5}}m/s\]
D.	\[{{10}^{2}}m/s\]
Answer» D. \[{{10}^{2}}m/s\]

Discussion

10719.	A soap bubble is given a negative charge, then its radius [MNR 1988; CPMT 1997; RPMT 1997;DCE 2000; BVP 2003]
A.	Decreases
B.	Increases
C.	Remains unchanged
D.	Nothing can be predicted as information is insufficient
Answer» C. Remains unchanged

Discussion

10720.	Assertion : An object can have constant speed but variable velocity. Reason : Speed is a scalar but velocity is a vector quantity.
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

10721.	Assertion : The ionising power of b-particle is less compared to a-particles but their penetrating power is more. Reason : The mass of b-particle is less than the mass of a-particle.
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

10722.	Assertion : Basic difference between an electric line and magnetic line of force is that former is discontinuous and the latter is continuous or endless. Reason : No electric lines of forces exist inside a charged body but magnetic lines do exist inside a magnet.
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

10723.	Assertion : Radiation is the speediest mode of heat transfer. Reason : Radiation can be transmitted in zig-zag 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» D. If the assertion and reason both are false.

Discussion

10724.	Assertion : The force of repulsion between atomic nucleus and a-particle varies with distance according to inverse square law. Reason : Rutherford did a-particle scattering experiment.
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

10725.	The carrier frequency generated by a tank circuit containing 1 nF capacitor and 10 mH inductor is [AFMC 2003]
A.	1592 Hz
B.	1592 MHz
C.	1592 kHz
D.	159.2 Hz
Answer» D. 159.2 Hz

Discussion

10726.	An electron jumps from the 4th orbit to the 2nd orbit of hydrogen atom. Given the Rydberg's constant \[R={{10}^{5}}c{{m}^{-1}}\]. The frequency in Hz of the emitted radiation will be [CPMT 1976]
A.	\[\frac{3}{16}\times {{10}^{5}}\]
B.	\[\frac{3}{16}\times {{10}^{15}}\]
C.	\[\frac{9}{16}\times {{10}^{15}}\]
D.	\[\frac{3}{4}\times {{10}^{15}}\]
Answer» D. \[\frac{3}{4}\times {{10}^{15}}\]

Discussion

10727.	A 100 g iron ball having velocity 10 m/s collides with a wall at an angle 30° and rebounds with the same angle. If the period of contact between the ball and wall is 0.1 second, then the force experienced by the wall is [CPMT 1997]
A.	10 N
B.	100 N
C.	1.0 N
D.	0.1 N
Answer» B. 100 N

Discussion

10728.	For high frequency, a capacitor offers [CPMT 1999; CBSE PMT 1999; AFMC 2001; Pb. PET 2001; J & K CET 2004]
A.	More reactance
B.	Less reactance
C.	Zero reactance
D.	Infinite reactance
Answer» C. Zero reactance

Discussion

10729.	Assertion : The time period of geostationary satellite is 24 hours. Reason : Geostationary satellite must have the same time period as the time taken by the earth to complete one revolution about its axis.
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

10730.	The lengths and radii of two rods made of same material are in the ratios 1 : 2 and 2 : 3 respectively. If the temperature difference between the ends for the two rods be the same, then in the steady state, the amount of heat flowing per second through them will be in the ratio [MP PET 2000]
A.	1: 3
B.	4 : 3
C.	8 : 9
D.	3 : 2
Answer» D. 3 : 2

Discussion

10731.	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

10732.	Assertion : A transistor is a voltage-operating device. Reason : Base current is greater than the collector current.
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

10733.	Assertion : The dominant mechanism for motion of charge carriers in forward and reverse biased silicon P-N junction are drift in both forward and reverse bias. Reason : In reverse biasing, no current flow through the junction.
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

10734.	If an electron oscillates at a frequency of 1 GHz it gives[DCE 1999]
A.	X-rays
B.	Mirowaves
C.	Infrared rays
D.	None of these
Answer» E.

Discussion

10735.	A circuit has a resistance of \[11\Omega ,\] an inductive reactance of \[25\Omega \] and a capacitative resistance of \[18\Omega .\] It is connected to an ac source of 260V and 50Hz. The current through the circuit (in amperes) is [Kerala PMT 2002]
A.	11
B.	15
C.	18
D.	20
Answer» E.

Discussion

10736.	A laser is a coherent source because it contains [JIPMER 2003]
A.	Many wavelengths
B.	Uncoordinated wave of a particular wavelength
C.	Coordinated wave of many wavelengths
D.	Coordinated waves of a particular wavelength
Answer» E.

Discussion

10737.	Number of electrons in one coulomb of charge will be [MP PMT/PET 1998; Pb. PMT 1999; AIIMS 1999; RPET 2001]
A.	\[5.46\times {{10}^{29}}\]
B.	\[6.25\times {{10}^{18}}\]
C.	\[1.6\times {{10}^{+19}}\]
D.	\[9\times {{10}^{11}}\]
Answer» C. \[1.6\times {{10}^{+19}}\]

Discussion

10738.	Assertion : If the displacement of the body is zero, the distance covered by it may not be zero. Reason : Displacement is a vector quantity and distance is a scalar quantity.
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

10739.	Assertion : A force act upon the earth revolving in a circular orbit about the sun. Hence work should be done on the earth. Reason : The necessary centripetal force for circular motion of earth comes from the gravitational force between earth and sun.
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

10740.	An electron in the n = 1 orbit of hydrogen atom is bound by 13.6 eV energy is required to ionize it is [MP PMT 2003]
A.	13.6 eV
B.	6.53 eV
C.	5.4 eV
D.	1.51 eV
Answer» B. 6.53 eV

Discussion

10741.	Assertion : A light body and heavy body have same momentum. Then they also have same kinetic energy. Reason : Kinetic energy does not depend on mass 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» E. If assertion is false but reason is true.

Discussion

10742.	The weight of an object in the coal mine, sea level, at the top of the mountain are \[{{W}_{1}},\ {{W}_{2}}\] and \[{{W}_{3}}\] respectively, then [EAMCET 1990]
A.	\[{{W}_{1}}<{{W}_{2}}>{{W}_{3}}\]
B.	\[{{W}_{1}}={{W}_{2}}={{W}_{3}}\]
C.	\[{{W}_{1}}<{{W}_{2}}<{{W}_{3}}\]
D.	\[{{W}_{1}}>{{W}_{2}}>{{W}_{3}}\]
Answer» B. \[{{W}_{1}}={{W}_{2}}={{W}_{3}}\]

Discussion

10743.	Assume that the acceleration due to gravity on the surface of the moon is 0.2 times the acceleration due to gravity on the surface of the earth. If \[{{R}_{e}}\] is the maximum range of a projectile on the earth?s surface, what is the maximum range on the surface of the moon for the same velocity of projection [Kerala (Engg.) 2001]
A.	\[0.2\,{{R}_{e}}\]
B.	\[2\,{{R}_{e}}\]
C.	\[0.5\,{{R}_{e}}\]
D.	\[5\,{{R}_{e}}\]
Answer» E.

Discussion

10744.	A man, standing between two cliffs, claps his hands and starts hearing a series of echoes at intervals of one second. If the speed of sound in air is 340 ms-1, the distance between the cliffs is [KCET 2004]
A.	340 m
B.	1620 m
C.	680 m
D.	1700 m
Answer» B. 1620 m

Discussion

10745.	If vm is the velocity of sound in moist air, vd is the velocity of sound in dry air, under identical conditions of pressure and temperature [KCET 2002, 03]
A.	vm > vd
B.	vm < vd
C.	vm = vd
D.	vmvd = 1
Answer» B. vm < vd

Discussion

10746.	It takes 2.0 seconds for a sound wave to travel between two fixed points when the day temperature is \[{{10}^{o}}\]C. If the temperature rise to \[{{30}^{o}}\]C the sound wave travels between the same fixed parts in [Orissa JEE 2003]
A.	1.9 sec
B.	2.0 sec
C.	2.1 sec
D.	2.2 sec
Answer» B. 2.0 sec

Discussion

10747.	Following sets of three forces act on a body. Whose resultant cannot be zero [CPMT 1985]
A.	10, 10, 10
B.	10, 10, 20
C.	10, 20, 23
D.	10, 20, 40
Answer» E.

Discussion

10748.	A plane is revolving around the earth with a speed of 100 km/hr at a constant height from the surface of earth. The change in the velocity as it travels half circle is [RPET 1998; KCET 2000]
A.	200 km/hr
B.	150 km/hr
C.	\[100\,\sqrt{2}\,km/hr\]
D.	0
Answer» B. 150 km/hr

Discussion

10749.	In a primary coil 5A current is flowing on 220 volts. In the secondary coil 2200V voltage produces. Then ratio of number of turns in secondary coil and primary coil will be [RPET 2003]
A.	1 : 10
B.	10 : 1
C.	1 : 1
D.	11 : 1
Answer» C. 1 : 1

Discussion

10750.	An AM wave has 1800 watt of total power content, For 100% modulation the carrier should have power content equal to
A.	1000 watt
B.	1200 watt
C.	1500 watt
D.	1600 watt
Answer» C. 1500 watt

Discussion

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

Assertion : A transformer cannot work on dc supply. Reason : dc changes neither in magnitude nor in direction.

A polyatomic gas \[\left( \gamma =\frac{4}{3} \right)\] is compressed to \[\frac{1}{8}\] of its volume adiabatically. If its initial pressure is \[{{P}_{o}}\], its new pressure will be [MP PET 1994; BHU 1995]

Assertion : The resolving power of an electron microscope is higher than that of an optical microscope. Reason : The wavelength of electron is more than the wavelength of visible light.

Assertion : Although the surfaces of a goggle lens are curved, it does not have any power. Reason : In case of goggles, both the curved surfaces have equal radii of curvature.

64 small drops of mercury, each of radius r and charge q coalesce to form a big drop. The ratio of the surface density of charge of each small drop with that of the big drop is [KCET 2002]

Assertion : If the angles of the base of the prism are equal, then in the position of minimum deviation, the refracted ray will pass parallel to the base of prism. Reason : In the case of minimum deviation, the angle of incidence is equal to the angle of emergence.

Assertion : A needle placed carefully on the surface of water may float, whereas a ball of the same material will always sink. Reason : The buoyancy of an object depends both on the material and shape of the object.

The current in series LCR circuit will be maximum when w is [Kerala PMT 2004]

Assertion : The 200 W bulbs glows with more brightness then 100 W bulbs. Reason : A 100 W bulb has more resistance than a 200 W bulb.

Assertion : Machine parts are jammed in winter. Reason : The viscosity of lubricant used in machine parts increase at low temperature.

Reactance of a capacitor of capacitance \[C\mu F\] for ac frequency \[\frac{400}{\pi }\] Hz is \[25\Omega \]. The value C is [MH CET 2002]

Assertion : Position-time graph of a stationary object is a straight line parallel to time axis. Reason : For a stationary object, position does not change with time.

If the diameter of a capillary tube is doubled, then the height of the liquid that will rise is [CPMT 1997]

Assertion : Linear momentum of a body changes even when it is moving uniformly in a circle. Reason : In uniform circular motion velocity remain constant.

Eddy currents are produced when [CBSE PMT 1993; AFMC 2002]

A liquid wets a solid completely. The meniscus of the liquid in a sufficiently long tube is [Kerala (Engg.) 2002]

A charge of \[40\mu \,C\] is given to a capacitor having capacitance \[C=10\mu \,F\]. The stored energy in ergs is [CPMT 2002]

In Bainbridge mass spectrograph a potential difference of 1000 V is applied between two plates distant 1 cm apart and magnetic field in B = 1T. The velocity of undeflected positive ions in m/s from the velocity selector is [RPMT 1998]

A soap bubble is given a negative charge, then its radius [MNR 1988; CPMT 1997; RPMT 1997;DCE 2000; BVP 2003]

Assertion : An object can have constant speed but variable velocity. Reason : Speed is a scalar but velocity is a vector quantity.

Assertion : The ionising power of b-particle is less compared to a-particles but their penetrating power is more. Reason : The mass of b-particle is less than the mass of a-particle.

Assertion : Basic difference between an electric line and magnetic line of force is that former is discontinuous and the latter is continuous or endless. Reason : No electric lines of forces exist inside a charged body but magnetic lines do exist inside a magnet.

Assertion : Radiation is the speediest mode of heat transfer. Reason : Radiation can be transmitted in zig-zag motion.

Assertion : The force of repulsion between atomic nucleus and a-particle varies with distance according to inverse square law. Reason : Rutherford did a-particle scattering experiment.

The carrier frequency generated by a tank circuit containing 1 nF capacitor and 10 mH inductor is [AFMC 2003]

An electron jumps from the 4th orbit to the 2nd orbit of hydrogen atom. Given the Rydberg's constant \[R={{10}^{5}}c{{m}^{-1}}\]. The frequency in Hz of the emitted radiation will be [CPMT 1976]

A 100 g iron ball having velocity 10 m/s collides with a wall at an angle 30° and rebounds with the same angle. If the period of contact between the ball and wall is 0.1 second, then the force experienced by the wall is [CPMT 1997]

For high frequency, a capacitor offers [CPMT 1999; CBSE PMT 1999; AFMC 2001; Pb. PET 2001; J & K CET 2004]

Assertion : The time period of geostationary satellite is 24 hours. Reason : Geostationary satellite must have the same time period as the time taken by the earth to complete one revolution about its axis.

The lengths and radii of two rods made of same material are in the ratios 1 : 2 and 2 : 3 respectively. If the temperature difference between the ends for the two rods be the same, then in the steady state, the amount of heat flowing per second through them will be in the ratio [MP PET 2000]

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 : A transistor is a voltage-operating device. Reason : Base current is greater than the collector current.

Assertion : The dominant mechanism for motion of charge carriers in forward and reverse biased silicon P-N junction are drift in both forward and reverse bias. Reason : In reverse biasing, no current flow through the junction.

If an electron oscillates at a frequency of 1 GHz it gives[DCE 1999]

A circuit has a resistance of \[11\Omega ,\] an inductive reactance of \[25\Omega \] and a capacitative resistance of \[18\Omega .\] It is connected to an ac source of 260V and 50Hz. The current through the circuit (in amperes) is [Kerala PMT 2002]

A laser is a coherent source because it contains [JIPMER 2003]

Number of electrons in one coulomb of charge will be [MP PMT/PET 1998; Pb. PMT 1999; AIIMS 1999; RPET 2001]

Assertion : If the displacement of the body is zero, the distance covered by it may not be zero. Reason : Displacement is a vector quantity and distance is a scalar quantity.

Assertion : A force act upon the earth revolving in a circular orbit about the sun. Hence work should be done on the earth. Reason : The necessary centripetal force for circular motion of earth comes from the gravitational force between earth and sun.

An electron in the n = 1 orbit of hydrogen atom is bound by 13.6 eV energy is required to ionize it is [MP PMT 2003]

Assertion : A light body and heavy body have same momentum. Then they also have same kinetic energy. Reason : Kinetic energy does not depend on mass of the body.

The weight of an object in the coal mine, sea level, at the top of the mountain are \[{{W}_{1}},\ {{W}_{2}}\] and \[{{W}_{3}}\] respectively, then [EAMCET 1990]

A man, standing between two cliffs, claps his hands and starts hearing a series of echoes at intervals of one second. If the speed of sound in air is 340 ms-1, the distance between the cliffs is [KCET 2004]

If vm is the velocity of sound in moist air, vd is the velocity of sound in dry air, under identical conditions of pressure and temperature [KCET 2002, 03]

It takes 2.0 seconds for a sound wave to travel between two fixed points when the day temperature is \[{{10}^{o}}\]C. If the temperature rise to \[{{30}^{o}}\]C the sound wave travels between the same fixed parts in [Orissa JEE 2003]

Following sets of three forces act on a body. Whose resultant cannot be zero [CPMT 1985]

A plane is revolving around the earth with a speed of 100 km/hr at a constant height from the surface of earth. The change in the velocity as it travels half circle is [RPET 1998; KCET 2000]

In a primary coil 5A current is flowing on 220 volts. In the secondary coil 2200V voltage produces. Then ratio of number of turns in secondary coil and primary coil will be [RPET 2003]

An AM wave has 1800 watt of total power content, For 100% modulation the carrier should have power content equal to