Moving Charges and Magnetism — Physics STD 12 Science — Question

An electron jumps from 5^th orbit to 4^th orbit of hydrogen atom. Taking the Rydberg constant as  per metre. What will be the frequency of radiation emitted

(a) 6.75

(b) 6.75

(c) 6.75

(d) None of these

Two identical conductors of copper and aluminium are placed in an identical electric fields. The magnitude of induced charge in the aluminium will be

(a) Zero	(b) Greater than in copper
(c) Equal to that in copper	(d) Less than in copper

A convex lens forms a real image of an object for its two different positions on a screen. If height of the image in both the cases be 8 cm and 2 cm, then height of the object is

(a) 16 cm

(b) 8 cm

(c) 4 cm

(d) 2 cm

The mass number of a nucleus is:

1. Always less than its atomic number.
2. Always more than its atomic number.
3. Equal to its atomic number.
4. Sometimes more than and sometimes equal to its atomic number.

From the following equations, pick out the possible nuclear reactions

(a)

(b)

(c)

(d)

In which of the following systems will the wavelength corresponding to n = 2 to n = 1 be minimum?

If half life of radium is 77 days. Its decay constant in day will be

(a) 3 /day

(b)

(c) 1 /day

(d) 6 /day

In an LCR series a.c. circuit, the voltage across each of the components. L, C and R is 50V. The voltage across the LC combination will be:

Focal length of a convex lens will be maximum for

(a) Blue light

(b) Yellow light

(c) Green light

(d) Red light

In a Ag voltameter 2.68 gm of silver is deposited in 10 min. The heat developed in 20Ω resistor during the same period will be

(a) 192 kJ

(b) 192 J

(c) 200 J

(d) 132 kJ