Electromagnetic Waves — Physics STD 12 Science — Question

If heat is supplied to an ideal gas in an isothermal process:

1. The internal energy of the gas will increase.
2. The gas will do positive work.
3. The gas will do negative work.
4. The said process is not possible.

When the distance between two charges is increased, the potential energy of the charges:

An antenna is a device

(a) That converts electromagnetic energy into radio frequency signal

(b) That converts radio frequency signal into electromagnetic energy

(c) That converts guided electromagnetic waves into free space electromagnetic waves and vice-versa

(d) None of these

Every series of hydrogen spectrum has an upper and  lower limit in wavelength. The spectral series which has an upper limit of wavelength equal to 18752 Å is (Rydberg constant  per metre)

(a) Balmer series

(b) Lyman series

(c) Paschen series

(d) Pfund series

If two lenses of +5 diopters are mounted at some distance apart, the equivalent power will always be negative if the distance is

(a) Greater than 40 cm	(b) Equal to 40 cm
(c) Equal to 10 cm	(d) Less than 10 cm

Red light is generally used to observe diffraction pattern from single slit. If blue light is used instead of red light, then diffraction pattern

(a) Will be more clear	(b) Will contract
(c) Will expanded	(d) Will not be visualized

The high temperature required to initiate the nuclear fusion reaction is to overcome the _______ present between the atoms.

Identify the correct options:

1. An ammeter should have small resistance.
2. An ammeter should have large resistance.
3. A voltmeter should have small resistance.
4. A voltmeter should have large resistance.

A thin, metallic spherical shell contains a charge Q on it. A point charge q is placed at the centre of the shell and another charge q₁ is placed outside it as shown in figure. All the three charges are positive. The force on the charge at the centre is: