Question # 1

Light appears to travel in straight lines since

Choose an answer

It is not absorbed by the atmosphere

It is reflected by the atmosphere

Its wavelength is very small

Its velocity is very large

When a hydrogen atom is bombarded the atom is excited to the n = 4 state of hydrogen atom.The energy released when the atom falls from n = 4 state to the ground state is

Choose an answer

1.275 eV

12.75 eV

5 eV

8 eV

The half life of a radio-isotope is 5 years The fraction of atoms decayed in this substance after 15 years will be

Choose an answer

1

3/4

7/8

5/8

Which of the following four statements is false?

Choose an answer

A body can have zero velocity and still be accelerated

A body can have a constant velocity and still have a varying speed

A body can have a constant speed and still have a varying velocity

The direction of the velocity of a acceleration is constant

Which one of the following phenomena is not explained by Huygen's construction of wavefront?

Choose an answer

Refraction

Reflection

Diffraction

Origin of spectra

Blood has a density

Choose an answer

Equal to water

Greater then water

Lesser then water

None of these

In LCR series AC circuit the phase angle between current and voltage is

Choose an answer

Any angle between 0 and ±π/2

π/2

π

Any angle between 0 and π/2

The mass defect for the nucleus of helium is 0.0303 a.m.u What is the binding energy per nucleon for helium in MeV?

Choose an answer

28

7

4

1

To get a resultant displacement of 10 m, two displacement vectors of magnitude 6 m and 8 m should be combined

Choose an answer

Parallel

Antiparallel

At angle 60°

Perpendicular to each other

A photocell with a constant p.d of V volt across it illuminated by a point source from a distance of 25 cm. When the source is moved to a distance of 1 m, the electrons emitted by the photocell

Choose an answer

Carry 1/4th their previous energy

Are 1/6th as numerous as before

Are 1/4th as numerous as before

Carry 1/4th their previous momentum

The essential distinction between X-rays andγ-rays is that

Choose an answer

γ-rays have smaller wavelength than X-rays

γ-rays emanate from nucleus while X-rays emanate from outer part of the atom

γ-rays have greater ionizing power than X-rays

γ-rays are more penetrating than X-rays

Two point charges A and B separated by a distance R attract each other with a force of 12 x 10^-3N. The force between A and B when the charges on them are doubled and distance is halved

Choose an answer

1.92 N

19.2 N

12 N

0.192 N

In an L-R circuit, time constant is that time in which current grows from zero to the value

Choose an answer

0.63 I_o

0.50 I_o

0.37 I_o

I_o

A monochromatic source of light is placed at a large distance d from a metal surface. Photoelectrons are ejected at rate n, kinetic energy being E. If the source is brought nearer to distance d/2, the rate and kinetic energy per photoelectron become nearly

Choose an answer

2n and 2E

4n and 4E

4n and E

N and 4E

What remains constant in the field of central force?

Choose an answer

Potential energy

Kinetic energy

Angular momentum

Linear momentum

A boy is dropped from a tower with zero velocity, reaches ground in 4s. The height of the tower is about

Choose an answer

80 m

20 m

160 m

40 m

A force of 10N is acting along y-axis. Its component along x-axis is

Choose an answer

10N

20N

100N

Zero N

The velocity of a particle at an instant is 10 m/s and after 5s the velocity of the particle is 20 m/s. The velocity 3s before in m/s is:

Choose an answer

8

4

6

7

A conducting wire is drawn to double its length. Final resistivity of the material will be

Choose an answer

Double of the original one

Half of the original one

One-fourth of the original one

Same as original one

In which of the following states does the incandescent substance give continuous spectrum?

Choose an answer

Vapours in atomic state

Vapours in molecular state

Solid or fluid in bulk state

Solid or fluid in plasma state

More Classes

Other Links

Physics General Science Test Hard Mode MCQs With Answers

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer