12583 + Mcqs in Physics Page 199 McqOptions

9901.	Assertion : At a point in space, the electric field points towards north. In the region, surrounding this point the rate of change of potential will be zero along the east and west. Reason : Electric field due to a charge is the space around the charge.
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

9902.	Assertion : Work done by or against gravitational force in moving a body from one point to another is independent of the actual path followed between the two points. Reason : Gravitational forces are conservative forces.
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

9903.	Assertion : The de-Broglie wavelength of a molecule varies inversely as the square root of temperature. Reason : The root mean square velocity of the molecule depends on the temperature. [AIIMS 1997]
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

9904.	Assertion : Charge is quantized Reason : Charge, which is less than 1 C is not possible
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

9905.	Pressure-temperature relationship for an ideal gas undergoing adiabatic change is \[(\gamma ={{C}_{p}}/{{C}_{v}})\] [CPMT 1992; MP PMT 1986, 87, 94, 97; Pb. PET 1998; DCE 2001; MP PET 2001; UPSEAT 1999, 2001; AFMC 2002]
A.	\[P{{T}^{\gamma }}=\] constant
B.	\[P{{T}^{-1+\gamma }}=\]constant
C.	\[{{P}^{\gamma -1}}{{T}^{\gamma }}=\]constant
D.	\[{{P}^{1-\gamma }}{{T}^{\gamma }}=\]constant
Answer» E.

Discussion

9906.	Assertion : Space rockets are usually launched in the equatorial line from west to east. Reason : The acceleration due to gravity is minimum at the equator.
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

9907.	In Milikan?s experiment, an oil drop having charge q gets stationary on applying a potential difference V in between two plates separated by a distance ?d?. The weight of the drop is [MP PMT 2001]
A.	\[qVd\]
B.	\[q\frac{d}{V}\]
C.	\[\frac{q}{Vd}\]
D.	\[q\frac{V}{d}\]
Answer» D. \[q\frac{V}{d}\]

Discussion

9908.	Assertion : We cannot think of magnetic field configuration with three poles. Reason : A bar magnet does exert a torque on itself due to its own field. [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

9909.	A particle is simultaneously acted by two forces equal to 4 N and 3 N. The net force on the particle is [CPMT 1979]
A.	7 N
B.	5 N
C.	1 N
D.	Between 1 N and 7 N
Answer» E.

Discussion

9910.	On passing 96500 coulomb of charge through a solution \[CuS{{O}_{4}}\] the amount of copper liberated is [MP PMT 2001]
A.	64 gm
B.	32 gm
C.	32 kg
D.	64 kg
Answer» C. 32 kg

Discussion

9911.	Assertion : A bus moving due north takes a turn and starts moving towards east with same speed. There will be no change in the velocity of bus. Reason : 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» F.

Discussion

9912.	A step-up transformer has transformation ratio of 3 : 2. What is the voltage in secondary if voltage in primary is 30 V [BHU 1998; Pb. PMT 2004]
A.	45 V
B.	15 V
C.	90 V
D.	300 V
Answer» B. 15 V

Discussion

9913.	Two equally charged, identical metal spheres A and B repel each other with a force 'F'. The spheres are kept fixed with a distance 'r' between them. A third identical, but uncharged sphere C is brought in contact with A and then placed at the mid-point of the line joining A and B. The magnitude of the net electric force on C is [UPSEAT 2004; DCE 2005]
A.	F
B.	3F/4
C.	F/2
D.	F/4
Answer» B. 3F/4

Discussion

9914.	The energy required to charge a capacitor of \[5\,\mu \,F\] by connecting a d.c. source of 20 kV is [Pb. PMT 2002]
A.	10 kJ
B.	5 kJ
C.	2 kJ
D.	1 kJ
Answer» E.

Discussion

9915.	Assertion : A tuning fork is made of an alloy of steel, nickel and chromium. Reason : The alloy of steel, nickel and chromium is called elinvar.
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

9916.	Acceleration due to gravity 'g' for a body of mass 'm' on earth's surface is proportional to (Radius of earth=R, mass of earth=M) [DCE 2004]
A.	\[GM/{{R}^{2}}\]
B.	\[{{m}^{0}}\]
C.	\[mM\]
D.	\[1/{{R}^{3/2}}\]
Answer» B. \[{{m}^{0}}\]

Discussion

9917.	In a Millikan's oil drop experiment the charge on an oil drop is calculated to be \[6.35\times {{10}^{-19}}C\]. The number of excess electrons on the drop is [MNR 1998]
A.	3.9
B.	4
C.	4.2
D.	6
Answer» C. 4.2

Discussion

9918.	Assertion : A laser beam 0.2 W power can drill holes through a metal sheet, whereas 1000 W torch-light cannot. Reason : The frequency of laser light is much higher then that of torch light. [AIIMS 1996]
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

9919.	Assertion : A negative acceleration of a body is associated with a slowing down of a body. Reason : Acceleration is 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» C. If assertion is true but reason is false.

Discussion

9920.	Assertion : In an adiabatic process, change in internal energy of a gas is equal to work done on or by the gas in the process. Reason : Temperature of gas remains constant in a adiabatic process.
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

9921.	Assertion : If an electron, while coming vertically from outerspace, enter the earth's magnetic field, it is deflected towards west. Reason : Electron has negative charge.
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

9922.	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

9923.	Assertion : The phenomenon of X-ray production is basically inverse of photoelectric effect. Reason : X-rays are electromagnetic waves.
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

9924.	The masses of two planets are in the ratio 1 : 2. Their radii are in the ratio 1 : 2. The acceleration due to gravity on the planets are in the ratio [MH CET 2004]
A.	1 : 2
B.	2 : 1
C.	3 : 5
D.	5 : 3
Answer» C. 3 : 5

Discussion

9925.	Water rises in a capillary tube when its one end is dipped vertically in it, is 3 cm. If the surface tension of water is\[75\text{ }\times \text{ }{{10}^{-3}}N/m\], then the diameter of capillary will be [MP PET 1989]
A.	0.1 mm
B.	0.5 mm
C.	1.0 mm
D.	2.0 mm
Answer» D. 2.0 mm

Discussion

9926.	Assertion : The specific charge of positive rays is not constant. Reason : The mass of ions varies with speed. [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» C. If assertion is true but reason is false.

Discussion

9927.	Assertion : If a charged particle is moving on a circular path in a perpendicular magnetic field, the momentum of the particle is not changing,. Reason : Velocity of the particle in not changing in the magnetic field.
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

9928.	The process of superimposing signal frequency (i.e. audio wave) on the carrier wave is known as [AIIMS 1987]
A.	Transmission
B.	Reception
C.	Modulation
D.	Detection
Answer» D. Detection

Discussion

9929.	Assertion : The possibility of an electric bulb fusing is higher at the time of switching ON and OFF Reason : Inductive effects produce a surge at the time of switch ON and OFF [AIIMS 2003]
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

9930.	A jet engine works on the principle of [CPMT 1973; MP PMT 1996]
A.	Conservation of mass
B.	Conservation of energy
C.	Conservation of linear momentum
D.	Conservation of angular momentum
Answer» D. Conservation of angular momentum

Discussion

9931.	Two identical blocks A and B, each of mass 'm' resting on smooth floor are connected by a light spring of natural length L and spring constant K, with the spring at its natural length. A third identical block 'C' (mass m) moving with a speed v along the line joining A and B collides with A. the maximum compression in the spring is [EAMCET 2003]
A.	\[v\sqrt{\frac{m}{2k}}\]
B.	\[m\sqrt{\frac{v}{2k}}\]
C.	\[\sqrt{\frac{mv}{k}}\]
D.	\[\frac{mv}{2k}\]
Answer» B. \[m\sqrt{\frac{v}{2k}}\]

Discussion

9932.	As we go from the equator to the poles, the value of g [CPMT 1975; AFMC 1995; AFMC 2004]
A.	Remains the same
B.	Decreases
C.	Increases
D.	Decreases upto a latitude of \[45{}^\circ \]
Answer» D. Decreases upto a latitude of \[45{}^\circ \]

Discussion

9933.	Which of the following is true for number of spectral lines in going form Layman series to Pfund series [RPET 2001]
A.	Increases
B.	Decreases
C.	Unchanged
D.	May decreases or increases
Answer» C. Unchanged

Discussion

9934.	Assertion : During a turn, the value of centripetal force should be less than the limiting frictional force. Reason : The centripetal force is provided by the frictional force between the tyres and the road.
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

9935.	When we rub our palms they gets heated but to a maximum temperature because
A.	Heat is absorbed by our palm
B.	Heat is lost in the environment
C.	Produced of heat is stopped
D.	None of the above
Answer» C. Produced of heat is stopped

Discussion

9936.	For the figure
A.	\[\overrightarrow{A}+\overrightarrow{B}=\overrightarrow{C}\]
B.	\[\overrightarrow{B}+\overrightarrow{C}=\overrightarrow{A}\]
C.	\[\overrightarrow{C}+\overrightarrow{A}=\overrightarrow{B}\]
D.	\[\overrightarrow{A}+\overrightarrow{B}+\overrightarrow{C}=0\]
Answer» D. \[\overrightarrow{A}+\overrightarrow{B}+\overrightarrow{C}=0\]

Discussion

9937.	In a parallel plate capacitor of capacitance C, a metal sheet is inserted between the plates, parallel to them. If the thickness of the sheet is half of the separation between the plates. The capacitance will be [KCET 2001]
A.	\[\frac{C}{2}\]
B.	\[\frac{3C}{4}\]
C.	\[4C\]
D.	\[2C\]
Answer» E.

Discussion

9938.	A bomb of 12 kg explodes into two pieces of masses 4 kg and 8 kg. The velocity of 8kg mass is 6 m/sec. The kinetic energy of the other mass is [MNR 1985; CPMT 1991; Manipal MEE 1995; Pb. PET 2004]
A.	48 J
B.	32 J
C.	24 J
D.	288 J
Answer» E.

Discussion

9939.	Assertion : Only microwaves are used in radar. Reason : Because microwaves have very small wavelength.
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

9940.	Assertion : Neutrons penetrate matter more readily as compared to protons. Reason : Neutrons are slightly more massive than protons. [AIIMS 2003]
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

9941.	Assertion : A capacitor of suitable capacitance can be used in an ac circuit in place of the choke coil. Reason : A capacitor blocks dc and allows ac only.
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

9942.	A resistance of 300 W and an inductance of \[\frac{1}{\pi }\] henry are connected in series to a ac voltage of 20 volts and 200 Hz frequency. The phase angle between the voltage and current is [Roorkee 1980]
A.	\[{{\tan }^{-1}}\frac{4}{3}\]
B.	\[{{\tan }^{-1}}\frac{3}{4}\]
C.	\[{{\tan }^{-1}}\frac{3}{2}\]
D.	\[{{\tan }^{-1}}\frac{2}{5}\]
Answer» B. \[{{\tan }^{-1}}\frac{3}{4}\]

Discussion

9943.	Two metal cubes \[A\] and \[B\] of same size are arranged as shown in the figure. The extreme ends of the combination are maintained at the indicated temperatures. The arrangement is thermally insulated. The coefficients of thermal conductivity of \[A\] and \[B\] are \[300\ W/m{{\ }^{o}}C\] and \[200\ W/m{{\ }^{o}}C\], respectively. After steady state is reached, the temperature of the interface will be [IIT 1996]
A.	\[{{45}^{o}}C\]
B.	\[{{90}^{o}}C\]
C.	\[{{30}^{o}}C\]
D.	\[{{60}^{o}}C\]
Answer» E.

Discussion

9944.	Water rises against gravity in a capillary tube when its one end is dipped into water because
A.	Pressure below the meniscus is less than atmospheric pressure
B.	Pressure below the meniscus is more than atmospheric pressure
C.	Capillary attracts water
D.	Of viscosity
Answer» B. Pressure below the meniscus is more than atmospheric pressure

Discussion

9945.	Two sound waves of slightly different frequencies propagating in the same direction produce beats due to [MP PET 2000]
A.	Interference
B.	Diffraction
C.	Polarization
D.	Refraction
Answer» B. Diffraction

Discussion

9946.	Three charges \[4q,\,Q\] and \[q\] are in a straight line in the position of 0, \[l/2\] and \[l\] respectively. The resultant force on \[q\] will be zero, if \[Q=\] [CPMT 1980]
A.	? q
B.	\[-\,2q\]
C.	\[-\frac{q}{2}\]
D.	\[4q\]
Answer» B. \[-\,2q\]

Discussion

9947.	A wave has velocity u in medium P and velocity 2u in medium Q. If the wave is incident in medium P at an angle of 30° then the angle of refraction will be [J & K CET 2005]
A.	30°
B.	45°
C.	60°
D.	90°
Answer» E.

Discussion

9948.	A current of 10A is passing through a long wire which has semicircular loop of the radius 20cm as shown in the figure. Magnetic field produced at the centre of the loop is [Orissa JEE 2003]
A.	\[10\,\pi \mu T\]
B.	\[5\,\pi \mu T\]
C.	\[4\,\pi \mu T\]
D.	\[2\,\pi \mu T\]
Answer» C. \[4\,\pi \mu T\]

Discussion

9949.	Assertion : A null vector is a vector whose magnitude is zero and direction is arbitrary. Reason : A null vector does not exist.
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

9950.	The time period of a simple pendulum on a freely moving artificial satellite is [CPMT 1984; AFMC 2002]
A.	Zero
B.	2 sec
C.	3 sec
D.	Infinite
Answer» E.

Discussion

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

Assertion : At a point in space, the electric field points towards north. In the region, surrounding this point the rate of change of potential will be zero along the east and west. Reason : Electric field due to a charge is the space around the charge.

Assertion : Work done by or against gravitational force in moving a body from one point to another is independent of the actual path followed between the two points. Reason : Gravitational forces are conservative forces.

Assertion : The de-Broglie wavelength of a molecule varies inversely as the square root of temperature. Reason : The root mean square velocity of the molecule depends on the temperature. [AIIMS 1997]

Assertion : Charge is quantized Reason : Charge, which is less than 1 C is not possible

Pressure-temperature relationship for an ideal gas undergoing adiabatic change is \[(\gamma ={{C}_{p}}/{{C}_{v}})\] [CPMT 1992; MP PMT 1986, 87, 94, 97; Pb. PET 1998; DCE 2001; MP PET 2001; UPSEAT 1999, 2001; AFMC 2002]

Assertion : Space rockets are usually launched in the equatorial line from west to east. Reason : The acceleration due to gravity is minimum at the equator.

In Milikan?s experiment, an oil drop having charge q gets stationary on applying a potential difference V in between two plates separated by a distance ?d?. The weight of the drop is [MP PMT 2001]

Assertion : We cannot think of magnetic field configuration with three poles. Reason : A bar magnet does exert a torque on itself due to its own field. [AIIMS 2002]

A particle is simultaneously acted by two forces equal to 4 N and 3 N. The net force on the particle is [CPMT 1979]

On passing 96500 coulomb of charge through a solution \[CuS{{O}_{4}}\] the amount of copper liberated is [MP PMT 2001]

Assertion : A bus moving due north takes a turn and starts moving towards east with same speed. There will be no change in the velocity of bus. Reason : Velocity is a vector-quantity.

A step-up transformer has transformation ratio of 3 : 2. What is the voltage in secondary if voltage in primary is 30 V [BHU 1998; Pb. PMT 2004]

The energy required to charge a capacitor of \[5\,\mu \,F\] by connecting a d.c. source of 20 kV is [Pb. PMT 2002]

Assertion : A tuning fork is made of an alloy of steel, nickel and chromium. Reason : The alloy of steel, nickel and chromium is called elinvar.

Acceleration due to gravity 'g' for a body of mass 'm' on earth's surface is proportional to (Radius of earth=R, mass of earth=M) [DCE 2004]

In a Millikan's oil drop experiment the charge on an oil drop is calculated to be \[6.35\times {{10}^{-19}}C\]. The number of excess electrons on the drop is [MNR 1998]

Assertion : A laser beam 0.2 W power can drill holes through a metal sheet, whereas 1000 W torch-light cannot. Reason : The frequency of laser light is much higher then that of torch light. [AIIMS 1996]

Assertion : A negative acceleration of a body is associated with a slowing down of a body. Reason : Acceleration is vector quantity.

Assertion : In an adiabatic process, change in internal energy of a gas is equal to work done on or by the gas in the process. Reason : Temperature of gas remains constant in a adiabatic process.

Assertion : If an electron, while coming vertically from outerspace, enter the earth's magnetic field, it is deflected towards west. Reason : Electron has negative charge.

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.

Assertion : The phenomenon of ­X-ray production is basically inverse of photoelectric effect. Reason : X-rays are electromagnetic waves.

The masses of two planets are in the ratio 1 : 2. Their radii are in the ratio 1 : 2. The acceleration due to gravity on the planets are in the ratio [MH CET 2004]

Water rises in a capillary tube when its one end is dipped vertically in it, is 3 cm. If the surface tension of water is\[75\text{ }\times \text{ }{{10}^{-3}}N/m\], then the diameter of capillary will be [MP PET 1989]

Assertion : The specific charge of positive rays is not constant. Reason : The mass of ions varies with speed. [AIIMS 1999]

Assertion : If a charged particle is moving on a circular path in a perpendicular magnetic field, the momentum of the particle is not changing,. Reason : Velocity of the particle in not changing in the magnetic field.

The process of superimposing signal frequency (i.e. audio wave) on the carrier wave is known as [AIIMS 1987]

Assertion : The possibility of an electric bulb fusing is higher at the time of switching ON and OFF Reason : Inductive effects produce a surge at the time of switch ON and OFF [AIIMS 2003]

A jet engine works on the principle of [CPMT 1973; MP PMT 1996]

As we go from the equator to the poles, the value of g [CPMT 1975; AFMC 1995; AFMC 2004]

Which of the following is true for number of spectral lines in going form Layman series to Pfund series [RPET 2001]

Assertion : During a turn, the value of centripetal force should be less than the limiting frictional force. Reason : The centripetal force is provided by the frictional force between the tyres and the road.

When we rub our palms they gets heated but to a maximum temperature because

For the figure

In a parallel plate capacitor of capacitance C, a metal sheet is inserted between the plates, parallel to them. If the thickness of the sheet is half of the separation between the plates. The capacitance will be [KCET 2001]

A bomb of 12 kg explodes into two pieces of masses 4 kg and 8 kg. The velocity of 8kg mass is 6 m/sec. The kinetic energy of the other mass is [MNR 1985; CPMT 1991; Manipal MEE 1995; Pb. PET 2004]

Assertion : Only microwaves are used in radar. Reason : Because microwaves have very small wavelength.

Assertion : Neutrons penetrate matter more readily as compared to protons. Reason : Neutrons are slightly more massive than protons. [AIIMS 2003]

Assertion : A capacitor of suitable capacitance can be used in an ac circuit in place of the choke coil. Reason : A capacitor blocks dc and allows ac only.

A resistance of 300 W and an inductance of \[\frac{1}{\pi }\] henry are connected in series to a ac voltage of 20 volts and 200 Hz frequency. The phase angle between the voltage and current is [Roorkee 1980]

Water rises against gravity in a capillary tube when its one end is dipped into water because

Two sound waves of slightly different frequencies propagating in the same direction produce beats due to [MP PET 2000]

Three charges \[4q,\,Q\] and \[q\] are in a straight line in the position of 0, \[l/2\] and \[l\] respectively. The resultant force on \[q\] will be zero, if \[Q=\] [CPMT 1980]

A wave has velocity u in medium P and velocity 2u in medium Q. If the wave is incident in medium P at an angle of 30° then the angle of refraction will be [J & K CET 2005]

A current of 10A is passing through a long wire which has semicircular loop of the radius 20cm as shown in the figure. Magnetic field produced at the centre of the loop is [Orissa JEE 2003]

Assertion : A null vector is a vector whose magnitude is zero and direction is arbitrary. Reason : A null vector does not exist.

The time period of a simple pendulum on a freely moving artificial satellite is [CPMT 1984; AFMC 2002]

Assertion : The phenomenon of X-ray production is basically inverse of photoelectric effect. Reason : X-rays are electromagnetic waves.