Nuclei — Physics STD 12 Science — Question

The energy of a photon of a characteristic X-ray from a Coolidge tube comes from:

In the Wheatstone's bridge shown, P = 2 Ω, Q = 3Ω, R = 6Ω and S = 8Ω. In order to obtain balance, shunt resistance across 'S' must be

(a) 2 Ω

(b) 3 Ω

(c) 6 Ω

(d) 8 Ω

When a piece of a ferromagnetic substance is put in a uniform magnetic field, the flux density inside it is four times the flux density away from the piece. The magnetic permeability of the material is

(a) 1

(b) 2

(c) 3

(d) 4

For the study of the helical structure of nucleic acids, the property of electromagnetic radiation generally used is

(a) Reflection

(b) Interference

(c) Diffraction

(d) Polarization

p-n junction diode acts as:

For substances hysteresis (B - H) curves are given as shown in figure. For making temporary magnet which of the following is best.

(a)

(b)

(c)

(d)

What is the path difference of destructive interference

(a) nl

(b) n(λ  + 1)

(c)

(d)

Suppose all the surfaces in the previous problem are rough. The direction of friction on B due to A:

1. Is upward.
2. Is downward.
3. Is zero.
4. Depends on the masses of A and B.

Relative permeability of iron is 5500, then its magnetic susceptibility will be

(a) 5500 × 107

(b) 5500 × 10–7

(c) 5501

(d) 5499

Generation, propagation and detection of electromagnetic waves is the basis of: