Question # 1

In photo electric cell, the photo electric current

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Decreases with increase in frequency of light

Depends on intensity and frequency of light

Does not depend upon the frequency of light and but depends upon intensity of light

Increases with increase in frequency of light

The rate at which the battery is supplying the electrical energy is the:

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Power output

Electrical power

Power input

Both A and C

The emf of a cell of negligible internal resistance is 2V. It is connected to the series combination of 𝟐𝛀, 𝟑𝛀 𝐚𝐧𝐝 𝟓𝛀 resistance. The potential difference across 𝟑𝛀 resistance will be in volt:

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0.6

2/3

3

6

Which row is correct for fission and for fusion?

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Produces larger nuclei

Produces smaller nuclei

Which one is the correct express of de-Broglie equation for the length of atoms of mass m at temp? T(k=Boltzmann’s constant):

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A particle executing one dimensional motion, finally comes to rest, what will be the angle between

acceleration and displacement during motion:

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0

π

𝜋/2

𝜋/4

Torque is necessary for producing.

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angular speed

linear acceleration

angular acceleration

none of these

A bomb of mass 30 kg at rest explodes into two pieces of masses 18 kg and 12 kg. The velocity of 18 kg mass is 6 ms¹ The KE of other mass is

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324 J

256 J

245 J

524 J

A light and a heavy body have equal momenta. Which one has greater K.E?

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The light body

The heavy body

The K.E are equa

Data is incomplete

The hydrogen atoms are excited to the stationary state designated by the principal quantum number n=4, the number of maximum spectral lines are observe:

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2

3

4

6

A wave which consists of a single, non-repetitive disturbance is called a

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Continuous wave

Longitudinal wave

Pulse

Transverse wave

A body crosses the topmost point of a vertical circle with critical speed. Itscentripetal acceleration, when the string is horizontal will be

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4g

3g

g

6g

A 100W, 220V bulb is operated on a 110V line, the power consumed is:

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25W

75W

50W

100W

The ratio of the SI unit to the C)G.S unit of torque is.

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10⁷

10⁹

10⁰

10³

A man has weight 980 N in a stationary lift. What will be his weight if the lift starts moving up with anacceleration of 4.9 ms^-2

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980 N

1470 N

1980 N

1460 N

The wavelength of light observed on the earth, form a moving star is found todecrease by 0.05%. Relative to the earth the star is

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moving away with a velocity of 1.5 x 10⁵m/s

moving away with a velocity of 1.5 x 10⁴m/s

coming closer with a velocity of 1.5 x 10⁵m/s

coming closer with a velocity of 1.5 x 10⁴m/s

In full wave rectification, the output D.C. voltage across the load is obtainedfor

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The positive half cycle of input A.C. (C) The complete cycle of input A.C.

The negative half cycle of input A.C.

The complete cycle of

All of the above

What will be efficiency of carnot engine when it is operated between the temperatures 47^oC and 127 ^oC:

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Reversible

Irreversible

Sometimes A and B

None of these

A piece of Aluminium (Al) and a piece of Germanium (Ge) are cooled T1 K to T2 K. The resistance of:

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Each of them increases

Each of them decreases

Al increases and Ge decreases

Al decreases and that of Ge increases

In nuclear fission reaction, when the products are 140X and 94Sr, the number of neutrons emitted is

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1

2

5

9

In photoelectric effect experiment, stopping potential depend upon

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Intensity of light

Frequency of light

Photoelectric current

Both A and B

The method by which only one half of A.C cycle is converted into direct current is called

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half wave amplification

half wave rectification

Full wave rectification

full wave amplification

The pressure exerted on the walls on the vessel by gas molecules is defined as:

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Force per unit volume

Energy per unit area

mass per unit volume

None of these

In photoelectric effect, electrons are emitted:

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Slowly

Intermittently

Both (a) & (b)

Instantly

Electric current is defined as:

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Flow of charges through conductor

Rate of flow of charges through conductor

Flow of electrons

Flow of protons

If a transverse wave has a speed of 10 m/ sec and frequency of 10 cycle/ sec itswavelength is:

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1 m

10^-2 cm

10 m

10 cm

Carnot cycle is:

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Reversible

Irreversible

Sometimes A, Sometimes B

None of these

A steady current is flowing in a conductor of non-uniform cross-section. Thecharge passing through any cross-section per unit time is

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Directly proportional to the area of cross-section

Inversely proportional to the area of cross-section

Proportional to square of the area of cross-section

Independent of the area of cross-section

The binding energy per nucleon is:

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Greater for heavy nuclei

Least for heavy nuclei

Greatest for light nuclei

Greatest for medium nuclei

The number of electrons emitted depend upon

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Colour of target surface

Shape of surface

Frequency of incident light

Intensity of incident light

A pure semiconductor has:

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An infinite resistance at 0^oC)

A finite resistance which does not depend upon temperature

A finite resistance which decreases with temperature

A finite resistance which increase with temperature

A rigid uniform bar of length 2.4 m is pivoted horizontally at its mid-point, weights are hung from two points of the bar as shown in diagram. To maintain horizontal equilibrium, a couple is applied to the bar: What is the torque and the direction of couple?

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40 N m clockwise

40 N m anti-clockwise

80 N m clockwise

80 N m anti-clockwise

Which of the following work is greater?

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+ 100J

0 J

- 100J

Both A and B are equal

The same retarding force is applied to stop a train. The train stops after 80 m. If the speed is doubled, then the Stopping distance will be:

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The same

Doubled

Halved

Four times

If an electron is accelerated such that its K.E is 4 times of its rest mass energythen thetotal relativistic energy of electrons is about

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5 × 10–12 J

4 × 10–13 J

3 × 10–13 J

6 × 10–12 J

When a gas is compressed:

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Its internal energy decreases

Its temperature decreases

Its temperature increases

None of these

The magnetic field produced due to the current in a straight wire is proportionalto the :

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Electric current

Conducting material

Length of the wire

Diameter of the wire

For a particle moving in uniform circular motion

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Velocity is transverse and acceleration is radical

Velocity is radial and acceleration is transverse

Both velocity and acceleration are radial

Both velocity and acceleration are transverse

Temperature of black body radiating at 270c is increased to 327oc, then emittedenergywill increase by

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2 times

12 times

16 times

4 times

The shortest wavelength of X-rays emitted from an X-rays tube depends on the:

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Current in the tube

Voltage applied to the tube

Nature of gas in the tube

Nature of material of tube

Resistance of 60 watt bulbs in 120V line is:

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20 ohms

240 ohms

0.15 ohms

180 ohms