Magnetism And Matter — Physics STD 12 Science — Question

The hysteresis cycle for the material of permanent magnet is:

Which of the following unit is not free from error?

Visible light passing through a circular hole forms a diffraction disc of radius 0.1mm on a screen. If an X-ray is passed through the same setup, the radius of the diffraction disc will be:

1. zero
2. < 0.1mm
3. 0.1mm
4. > 0.1m

The distance between the body centred atom and a corner atom in sodium (a = 4.225 Å) is

(a) 3.66 Å

(b) 3.17 Å

(c) 2.99 Å

(d) 2.54 Å

Select the correct statements:

1. A simple harmonic motion is necessarily periodic.
2. A simple harmonic motion is necessarily oscillatory.
3. An oscillatory motion is necessarily periodic.
4. A periodic motion is necessarily oscillatory.

Magnitude of pursuit velocity does not depend on :

γ-rays radiation can be used to create electron-positron pair. In this process of pair production, γ-rays energy cannot be less than

(a) 5.0 MeV

(b) 4.02 MeV

(c) 15.0 MeV

(d) 1.02 MeV

The refractive indices of water and glass with respect to air are 1.2 and 1.5 respectively. The refractive index of glass with respect to water is

(a) 0.6

(b) 0.8

(c) 1.25

(d) 1.75

The ionization potential for second He electron is

(a) 13.6 eV

(b) 27.2 eV

(c) 54.4 eV

(d) 100 eV

Which of the following rays are not electromagnetic waves

(a) g-rays

(b) b-rays

(c) Heat rays

(d) X-rays