Atoms — Physics STD 12 Science — Question

When X  rays pass through a strong uniform magnetic field, Then they

(a) Do not get deflected at all

(b) Get deflected in the direction of the field

(c) Get deflected in the direction opposite to the field

(d) Get deflected in the direction perpendicular to the field

An inductor, a resistor and a capacitor are joined in series with an AC source. As the frequency of the source is slightly increased from a very low value, the reactance of the.

Magnitude of pursuit velocity does not depend on :

A charged particle moves in a uniform magnetic field. The velocity of the particle at some instant makes an acute angle with the magnetic field. The path of the particle will be:

1. A straight line.
2. A circle.
3. A helix with uniform pitch.
4. A helix with nonuniform pitch.

Bohr's atom model assumes

(a) The nucleus is of infinite mass and is at rest

(b) Electrons in a quantized orbit will not radiate energy

(c) Mass of electron remains constant

(d) All the above conditions

Which of the following is a fusion reaction?

The rest energy of an electron is 0.511 MeV. The electron is accelerated from rest to a velocity 0.5 c. The change in its energy will be

(a) 0.026 MeV

(b) 0.051 MeV

(c) 0.079 MeV

(d) 0.105 MeV

Magnetic meridian is a

(a) Point

(b) Horizontal plane

(c) Vertical plane

(d) Line along N-S

In image formation from spherical mirrors, only paraxial rays are considered because they:

1. Are easy to handle geometrically.
2. Contain most of the intensity of the incident light.
3. Form nearly a point image of a point source.
4. Show minimum dispersion effect.