Question # 1

Which of the following does not have the same units:

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Work

Heat

Kinetic energy

Power

When a radioactive nucleus remits a beta particle, the proton neutron ratio:

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Decreases

Increases

Remain same

None of the above

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

select Which one of the following is not performing projectile motion

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A gas filled balloon

) Bullet fired from gun

A football kicked

A baseball shot

Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and v respectively. These trucks collide and stick together. What is the speed of the trucks after the collision?

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v/4

v/2

v

5v/4

When resistances are connected in Parallel, the effective resistance will be

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Product of the reciprocals of the individual resistances

Product of the individual resistances

Sum of the reciprocals of the individual resistances

Sum of the individual resistances

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

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

A body of mass m tied to a string is moved in a vertical circle of radius r. the difference in tensions at the lowest point and the highest point is.

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2 mg

4 mg

6 𝑚g

8 mg

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 the same value of resistors the output of non-inverting amplifier compared to the output of inverting amplifier is, (ignoring phase difference)

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Greater

Equal

Smaller

Undefined

Moving photons posses:

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Energy

Momentum

Wavelength

All of these

In a gravitational field when work done by gravity is negative then

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P.E increases

P.E decrease

None

P.E remains same

Maximum speed of electrons in X-rays tube which is producing X-rays photons of frequency f is

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The junction potential for Germanium is;

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3v

0.3 v

7v

0.7 v

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

The relative permittivity of air is

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1

3.7

7.8

1.0006

A cell of negligible resistance and e.m.f 2 V is connected across a series combination of 2,3 and 5 ohms. The p.d. across the 3 Ω resistor is

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0.6 V

1/3 V

2/3 V

4/3 V

Two point charges repel each other with a force of 4× 𝟏𝟎−𝟓 newton at a distanceof meter. Two charges are

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Both positive

Alike

Both Negative

Unlike

Which of the following have maximum ionization power?

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𝛼 −rays

𝛽 −rays

𝛾 −rays

Same for all

Only those processes are probable to take place for which entropy os the system:

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Increases

Remains constant

Both A and B are correct

None of above

The energy stored in wound watch spring is

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K.E.

P.E.

heat energy

chemical energy

When a particle moves in a circle the angle between it linear velocity and the angular velocity is always

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0°

180°

90°

none of them

For a normal AC cycle, during T/2 to T the diode act as:

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Open switch

full wave rectifier

Close switch

All are correct

The maximum energy of the photoelectrons depends upon:

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Frequency of incident light

Intensity of incident light

Nature of metal

Both (a) & (c)

Brownian motion confirms the truth of :

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Wave theory of light

Boyle's law

Kinetic theory of gases

Adiabatic process

Ten second after an electric fan is turned on, the fan rotates at 300rev/min. its average angular acceleration is

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30 rad/s²

3.14 rad/s²

30 rev/s²

500 rev/s²

If a rotating body is moving counter clockwise, direction of angular velocity will be

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along linear velocity

towards the center

along the axis of rotation

away from center

The frequency of an open pipe is f. if one end is closed then its fundamental frequencywill be:

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f/2

3f/4

f

2f

What happens to the centripetal acceleration of a particle, when its speed is doubled and angular velocity is halved?

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halved

doubled

remain unchanged

becomes four times

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

A 4 m long string fixed at its ends resonate in 4 segments. The wavelength of the waveis:

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4m

0.5m

2m

0.25 m

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

The efficiency of full wave rectifier is:

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25.6%

81.2%

81.6%

71.2%

The direction of force experienced by a moving in a magnetic field will be:

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Parallel to the field

Opposite to the field

Parallel to its direction of motion

Perpendicular to both the field and the velocity vector

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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The diodes works on

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A.C

D.C

both A and B

None of these

What is the momentum of a photon of light of wavelength 500 nm in kgm/s:

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1.32 × 10−21

1.32 × 10−23

1.32 × 10−25

1.32 × 10−27

De-Broglie received the Nobel prize in

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1929

1937

1928

1924

Light of frequency 1.5 times the threshold frequency is incident on a photo sensitive material. If the frequency is halved and intensity is doubled the photo electric current becomes

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Four times

Half

Double

Zero

First law of thermodynamics is merely a statement of law of conversation of:

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Energy

Angular momentum

Change

Linear momentum