Chapter 15

What is the wavelength range of visible light? (A) \(10 \mathrm{~A}\) to \(100 \mathrm{~A}\) (B) \(4000 \mathrm{~A}\) to \(7000 \mathrm{~A}\) (C) \(8000 \AA\) to \(10000 \AA\) (D) \(10000 \AA\) to \(15000 \AA\)

Unit of \(\mu_{0} \mathrm{c}\) is same as that of (A) current (B) resistance (C) electric charge (D) velocity

In electromagnetic spectrum, the visible light lie between (A) radiowaves and microwaves (B) ultraviolet rays and infrared rays (C) ultraviolet rays and \(\mathrm{x}\) rays (D) infrared rays and microwaves

The oscillating electric and magnetic field vectors of an electromagnetic waves far away from source are oriented along (A) Mutually perpendicular direction and differ in phase by \(90^{\circ}\) (B) Mutually perpendicular and in same phase (C) In same direction and in same phase (D) In same direction and differ in phase by \(90^{\circ}\)

The sun delivers \(10^{3} \mathrm{Wm}^{-2}\) of electromagnetic flux to earth's surface. The total power that is incident on a roof of dimension \(8 \mathrm{~m} \times 20 \mathrm{~m}\) will be (A) \(4 \times 10^{5} \mathrm{w}\) (B) \(2.56 \times 10^{4} \mathrm{w}\) (C) \(6.4 \times 10^{5} \mathrm{w}\) (D) \(1.6 \times 10^{5} \mathrm{w}\)

Bolometer is used to detect (A) infrared rays (B) ultraviolet rays (C) x rays (D) \(\gamma\) rays

Range of frequency of microwaves is about (A) \(530 \mathrm{kHz}\) to \(1710 \mathrm{kHz}\) (B) \(54 \mathrm{MHz}\) to \(890 \mathrm{MHz}\) (C) \(3 \mathrm{GHz}\) to \(300 \mathrm{GHz}\) (D) \(4 \times 10^{14} \mathrm{~Hz}\) to \(7 \times 10^{14} \mathrm{~Hz}\)

SI unit of displacement current is (A) coulomb (B) ampere (C) faraday (D) volt

The frequencies of \(\mathrm{x}\) rays, \(\gamma\) rays and ultraviolet rays are respectively \(\mathrm{p}, \mathrm{q}\) and \(\mathrm{r}\) then (A) \(pr\) (B) \(p>q, q>r\) (C) \(p>q, q

At room temperature, if the relative permittivity of water is 80 and the relative permeability be \(0.0222\) then the velocity of light in water is \(\mathrm{m} / \mathrm{s}\) (A) \(2.5 \times 10^{8}\) (B) \(2.26 \times 10^{8}\) (C) \(3.5 \times 10^{8}\) (D) \(3 \times 10^{8}\)