Question # 1

The temperature at which all the gases become liquid is called:

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273 K

-273 K

Absolute Zero

Both (B) and (C)

A body of mass 3 Kg lies on the surface on the table 2m high. It is moved on the surface by 4m. The change of P.E will be:

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Zero

9.8 J

19.6 J

329 J

The unit of gain (G) for non-inverting amplifier is

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Ampere

ohm

Volt

None of these

A point on the rim of a wheel 4m in diameter has a velocity of 1600 cm s-1. The angular velocity of the wheel is

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2 rad s^-1

4 rad s^-1

6 rad s^-1

8 rad s^-1

Davisson and Germer, in their experiment used:

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Nickle crystal

Lead crystal

Graphite crystal

Glass

The most penetrating radiations out of the following is that of

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𝛾-rays

β-rays

α-particles

X-rays

The product of resistance and conductance of a resistors is equal to:

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1

Conductivity

Resistivity

Zero

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

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Decreases

Increases

Remain same

None of the above

In uniform circular motion, the factor that remains constant is:

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Linear velocity

Acceleration

Speed

All of these

The time period of revolution of geostationary satellite is

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1440 minutes

24 minutes

84 minutes

none of these

The junction potential for Germanium is;

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3v

0.3 v

7v

0.7 v

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

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

A process in which no heat enters or leaves the system is called.

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Adiabatic process

Isothermal process

Isochoric process

None of these

Inverting amplifier circuits have

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A very high input impendance

A very low input impendance

A low output impendance

Both A and C

When two semiconductors of p- and n-type are brought into contact, they from a p-n junction which act like a:

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Conductor

Amplifier

Oscillator

Rectifier

A.H Compton studied the scattering of X-rays by loosely bound electrons from a graph target in:

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1905

1911

19251

1923

Number of spark plugs needed in diesel engine is:

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Four

Five

Six

None of these

A human eye can detect the electromagnetic radiations of the type:

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Infrared radiations

For- infrared radiations

X-rays radiations

Red radiations

𝑎, 𝖰 𝒂𝒏𝒅 radiations come out of radioactive substance:

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Spontaneously

When it is put in a reactor

When it is heated

Under pressure

No of spark plugs needed in diesel engine is:

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Four

Five

Six

None of these

When an electron in an atom goes from a lower to higher its:

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K.E. increases, P.E. decreases

K.E. increases

P.E increases

K.E. decrease, P.E. increases

The energy of photon of wavelength 1240 nm is:

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0.5 eV

1.0 eV

1.5 eV

2.0 eV

The time period of a geostationary satellite above the surface of the earth is.

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24 hours

12 hours

365 days

none of these

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 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

If the temperature difference between hot and cold body is greater the heat engine is:

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Not efficient

Less efficient

More efficient

NOne of above

The temperature scale approved in SI units is:

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Calslus scale

Kelvin scale

Fehrenhelt scale

None of these

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

While dealing with the processes i thermodynamics, the working substances is usually:

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Oxygen gas

Hydrogen gas

Ideal gas

None of these

The rate of change of momentum of a molecule is equal to:

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Pressure

Work

Density

Force

Two satellites are going around the earth at a height of 250 km and 450 km respectively. If angular speed for both is same, then centripetal acceleration will be.

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more for first

more for second

same for both

nothing can be decided

If P is the pressure and V is the volume, Then PV will represent:

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Power

Work

Force

None of these

The angular analogue of linear displacement is called

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angular velocity

angular displacement

angular momentum

moment of force

Kinetic energy of a body moving with speed of 10 ms-1 is 30 J. If its speed becomes30 ms-1 then its K.E becomes

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10J

270 J

90J

180 J

When two objects come to common temperature, the body is said to be in:

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Static equilibrium

Dynamic equilibrium

Thermal equilibrium

None of these

Resistance of 60 watt bulbs in 120V line is:

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20 ohms

240 ohms

0.15 ohms

180 ohms

If a car moves with a uniform speed of 2 ms-1 in a circle of radius 0.4m. Its angular speed is

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4 rad. s^-1

1.6 rad. s^-1

5 rad. s^-1

2.8 ms^-1

In order to increase the K.E of ejected photo electrons, there should be an increase in:

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Intensity of radiation

NoneI

Frequency of radiation

Both (b) & (c)

A body is moving in a circle with a constant speed. it has

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a constant velocity

a constant acceleration

a velocity of constant magnitude

an acceleration of constant magnitude

The motion of molecules in gases i:

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Orderly

Random

Circular

All of these