Which of the following electromagnetic radiations is used for viewing objects through fog 

(a)

microwave

(b)

gamma rays

(c)

X- rays

(d)

infrared

If E = E_o sin[10⁶ x -ωt] be the electric field of a plane electromagnetic wave, the value of ω is_____.

(a)

0.3 x 10⁻¹⁴ rad s⁻¹

(b)

3 x 10⁻¹⁴ rad s⁻¹

(c)

0.3 x 10¹⁴ rad s⁻¹

(d)

3 x 10¹⁴ rad s^-1

The electric and magnetic fields of an electromagnetic wave are _____.

(a)

in phase and perpendicular to each other

(b)

out of phase and not perpendicular to each other

(c)

in phase and not perpendicular to each other

(d)

out of phase and perpendicular to each other

The wavelength range of ultra violet radiation is _________________.

(a)

6x10^-10 to 4x10^-7m

(b)

4x10^-7 to 7x10^-7m

(c)

6x10^-10 to 4x10^-10m

(d)

7x10^-7 to 4x10^-9m

The phase and orientation of the magnetic vector associated with electromagnetic oscillations differ respectively from those of the corresponding electric vectors by _______________.

(a)

zero, zero

(b)

\(\frac{\pi}{2}\),\(\frac{\pi}{2}\)

(c)

0, \(\frac{\pi}{2}\)

(d)

0,\(\frac{\pi}{2}\)

In vacuum speed of light depends upon ______________.

(a)

colour

(b)

wavelength

(c)

frequency

(d)

none of the above

Short wave bands are upto frequencies _______________.

(a)

54 KHz

(b)

5.4 MHz

(c)

54 MHz

(d)

54 GHz

The correct definition of spectrum is ____________.

(a)

band of colours

(b)

band of white light

(c)

band of frequencies

(d)

band of amplitudes

The spectra used for making dyes is _____________.

(a)

line spectra

(b)

continuous absorption spectra

(c)

fraunhofer spectra

(d)

band absorption spectra

Band spectra are obtained from _________.

(a)

atoms

(b)

molecules

(c)

solids

(d)

semisolids

Calcium or Barium salts in bunsen flame, CO₂, N₂ molecule, NH₃ gas in a discharge tube gives_______.

(a)

line emission spectra

(b)

continuous emission spectra

(c)

line absorption spectra

(d)

band spectra

The value of \(\frac { 1 }{ \sqrt { { \mu }_{ 0 }{ \varepsilon }_{ 0 } } } \) _________

(a)

3 x 10^-8 m/s

(b)

2.25 x 10⁸ m/s

(c)

3 x 10⁸ m/s

(d)

2.25 x 10⁸ m/s

The rays used in weather forecasting is ___________.

(a)

I-R rays

(b)

U-V rays

(c)

X - rays

(d)

μ-Waves

Electromagnetic waves are __________ waves.

(a)

longitudinal

(b)

Transverse

(c)

mechanical

(d)

sound

Angle between the electric and magnetic component of EM wave is ______________.

(a)

0

(b)

π/4

(c)

π/2

(d)

π

In E.M. waves, the variations in electric and magnetic fields are at an angle of________.

(a)

0°

(b)

60°

(c)

90°

(d)

270°

In an electromagnetic wave, the electric and magnetic fields are at an angle ___________ to the direction of propagation.

(a)

270°

(b)

90°

(c)

180°

(d)

67°

The wavelength range of x-rays is _________ (m).

(a)

10^-4 to 10^-2

(b)

10^-14 to 10^-9

(c)

10^-10 to 3 X 10^-8

(d)

10^-3 to 10^-5

Vacuum tubes produces ________

(a)

Visible light

(b)

RF waves

(c)

UV rays

(d)

Microwaves

Microwaves ovens are the domestic application of ________ wave.

(a)

UV

(b)

visible

(c)

radio

(d)

micro

________ lamps are used in physiotherapy.

(a)

IR

(b)

UV

(c)

visible

(d)

૪-rays

________ radiations are used to study atomic structure.

(a)

UV

(b)

IR

(c)

X-rays

(d)

Gamma

______ radiations are used in destroying bacteria.

(a)

UV

(b)

IR

(c)

X-ray

(d)

Gamma rays

_________ emission spectrum is used to identify the gas used.

(a)

Continuous

(b)

Line

(c)

Band

(d)

Solid

The dark lines in the solar spectrum are called _______ lines.

(a)

Fresnel

(b)

Newton

(c)

Compton

(d)

Fraunhofer