Online Test

Question # 1

The half life of radium-226 is

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238 years

4.5 x 10⁹years

1620 years

332 years

We can divide the optical fibres on the basis of the mode by which they propagate light in

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two types

three types

four types

many types

When will a photon stimulate high energy atoms to fall to ground state?

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when the energy of the photon is equal to the energy difference between high energy and ground state

when the photon has very high energy

when the energy of the photon is greater than a certain value

when the energy of the photon is greater than the energy difference between high energy and ground state

Wavelength of light, on the average, is given by:

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10^-14m

10^-10m

10^-6m

10^-4m

Mechanical waves on the surface of a liquid are

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Transverse

Longitudinal

Torsional

Both transverse and longitudinal

The smallest portion of a crystal lattice that if repeated in three-dimensions will generate the entire lattice is called:

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Unit cell

Lattice plane

Crystal

None of these

Fringe spacing in YDS experiment will be maximum if we use

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Red light

Green light

Violet light

Blue light

The flux is SI unit passing through any closed surface enclosing a charge of 8.85 X 10^-12Coulomb is:

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1

0.1

10⁶

8.85 X 10^-12

8.85 X 10¹²

M.K.S. unit of pressure

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Atmosphere

Dynes per sq.cm

Meter

Pascal

In Wilson cloud chamber, the β-particle leave

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Straight and continuous tracks

No definite tracks

Thin and continuous tracks

Thin and discontinuous tracks

Time period of a vibrating body is

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Time to take 1/2 vibration

Time to take 1 vibrations

Time for 30 vibrations

None of these

On heating, it becomes a very viscous liquid at almost

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500 C^o

800 C^o

900 C^o

1000 C^o

Volume of metal cylinder with the help of a vernier callipers of least count 0.01 cm when diameter is 1.22 cm and length 5.35 cm. Find its uncertainty as

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6.02 ± 0.1 cm³

6.2 ± 0.1 cm³

6.25 ± 0.1 cm²

6.3 ± 0.1 cm³

Polarization ________ the capacitance.

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Increases

Decreases

Changes

No effect

On colliding in a closed container the gas molecules

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Transfer momentum to the walls

Momentum becomes zero

Move in opposite directions

Perform Brownian motion

The ratio of stress/strain is called as

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Modulus of elasticity

Bulk modulus

Shear modulus

Young's modulus

Microwaves are used because they travel in a

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Narrow beam

Straight line

Easily pass through Earth atmosphere

All of these

Which of the following changes at an antinode in a stationary wave?

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Density only

Pressure only

Both pressure and density

Neither pressure nor density

Relativistic mechanics was developed by

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Davison and Germer

Heisenberg

Max. Planck

Albert Einstein

A lift is moving downwards at a very high constant speed. A passenger present inside the lift standing on a weighing machine would notice that his weight

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is shown as zero on the scale

becomes zero

remains constant at a value less than this real weight

remains the same as his real weight

If mass attached to a spring is replaced by another mass four times then time period of mass spring system becomes

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2 times

4 times

6 times

8 times

The original source of solar energy is

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Moon

Sun

Stars

Earths

At low frequency and large reactance the current will be

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Very small

Small

Large

None of these

Two bodies of mass 1 kg and 2kg have equal momentum.Then the ratio of their kinetic energies is

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2 : 1

3 : 1

1 : 3

1 : 1

Weightlessness experienced by the spaceship is due to

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Absence of gravity

Absence of inertia

Free fall of spaceship

All of these

Thermisters are made by heating under high pressure

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Semiconductor ceramic

Insulators

Metals

None of these

The light from the sun reaches to earth with wavefronts

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Spherical

Cylindrical

Plane

None of these

Magnetic field is a:

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Vector quantity

Scalar quantity

Vector as well as scalar quantity

Neither A nor B

Any of A or B

In an astronomical telescope the eye piece has the focal length f_e if

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Short

Long

Extremely long

None of these

Shear modulus for brass is

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36

39

51

65

Which one of the following is an example of irreversible process

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Work done against friction

Magnetizing a substance

Isothermal expansion of gas

Melting of ice

Acceleration of a body is negative if the velocity of the body is

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constant

increasing

decreasing

none of them

If P is the pressure of gas than K.E per unit volume of gas is

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P/2

P

3/2 P

2P

Bouncing off the squash ball several times from wall bears no

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Total displacement

Average velocity

Both

None of these

Which of the following undergo fission reaction easily by slow moving neutrons?

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U-235,P-239

P-239,Th-234

U-238,Rn-232

Th-234,U-238

As cross-sectional area of the pipe decreases the speed of fluids must increase according to

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Bernoulli's equation

Venture's reaction

Equation of continuity

Torricelli's theorem

Radiotherapy is often used in the treatment of cancer with

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Na-34

I-31

cobalt-60

C-12

A body will be in translation equilibrium only if the vector sum of all the external forces acting on a body is equal to

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Unity

Zero

Maximum

Double

In an electric generator an induced emf is also generated when

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Coil has constant area

Constant magnetic field

Constant frequency

All of them

At low frequency the certain capacitors have

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Low reactance

Large reactance

Very large reactance

None of these

The beam of the electrons is provided by

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Ionization of atoms

Photoemission

Electron gun

None of these