Electromagnetic Spectrum

Q.

Define wavelength

Q.

Write a short note on light

Q.

Differentiate between the primary colours and secondary colours:

Q.

In a new system of units called star units, $1\mathrm{kg}*=10\mathrm{kg},1\mathrm{m}*=1\mathrm{km}$ and $1\mathrm{s}*=1\min$, what will be the value of $1\mathrm{J}$ in the new system?

1. $2.4\times {10}^{-5}\mathrm{J}$

2. $3.6\times {10}^{-4}\mathrm{J}$

3. $4.2\times {10}^{-3}\mathrm{J}$

4. $4.2\times {10}^{-2}\mathrm{J}$

Q. Which one of the following colours has the shortest wavelength?

1. Red
2. Green
3. Violet
4. Orange

Q.

How do you calculate the frequency of red light?

Q.

State the correct sequence (1-7) of colors in the spectrum formed by the prisms A and B, shown in Figure 15.2

Q.

Write a short note on the following terms:

Polychromatic light

Q.

What is a monochromatic source of light?

Q.

Wave number is defined as the number of wavelengths per unit length.

1. True

2. False

Q.

Write a short note on the following term:

Monochromatic light

Q.

What is the longest electromagnetic wave?

Q. Most of the waves in the electromagnetic spectrum are:

1. red light
2. blue light
3. green light
4. invisible

Q. A wave with low frequency would have relatively ________.

1. high energy and a short wavelength
2. high energy and a long wavelength
3. low energy and a long wavelength
4. low energy and a short wavelength

Q. Which of the following type of waves have the shortest wavelength?

1. Radio waves
2. X-rays
3. Micro waves
4. Ultra violet waves

Q. Arrange the following electromagnetic waves in increasing order of their frequencies (i.e., begin with the lowest frequency): Visible light, $\gamma$ rays, X rays, micro waves, radio waves, infrared radiations and ultraviolet radiations.

Q.

The appearance of the colour of an object depends upon the colour of light that it absorbs.

1. True
2. False

Q.

A star emits light of $5500$ wavelengths. It appears blue to an observer on the earth, which means

Q. What will be the longest wavelength line in Balmer series of spectrum of H-atom

Q.

The number of waves in the fourth Bohr orbit of hydrogen is:

1. 3

2. 4

3. 9

4. 12

Q. Which of the following is correct for the increasing order of wavelengths of colour?

1. Orange $<$ yellow $<$ red $<$ blue
2. Red $<$ blue $<$ orange $<$ yellow
3. Blue $<$ yellow $<$ orange $<$ red
4. Yellow $<$ blue $<$ orange $<$ red

Q.

The transverse nature of light is shown by

1. Interference of light

2. Refraction of light

3. Polarization of light

4. Dispersion of light

Q. Arrange the following radiations in the order of their increasing wavelength:
$X$-rays, infra red rays, radio waves, gamma rays and micro waves.

1. Gamma rays, $X$-rays, infra red rays, radio waves, micro waves.
2. Gamma rays, micro waves, $X$-rays, infra red rays, radio waves.
3. Gamma rays, infra red rays, $X$-rays, micro waves, radio waves.
4. Gamma rays, $X$-rays, infra red rays, micro waves, radio waves.

Q.

How many types of analyzers are there?

Q.

What is the frequency spectrum of a signal?

Q.

What is Multichromatic light?

Q. If we denote microwaves, X rays, infrared, gamma rays, ultra-violet, radio waves and visible parts of the electromagnetic spectrum by M, X, I, G, U, R and V, the following is the arrangement in ascending order of wavelength :

1. R, M, I, V, U, X and G
2. M, R, V, X, U, G and I
3. G, X, U, V, I, M and R
4. I, M, R, U, V, X and G

Q.

What is the smallest electromagnetic wave?

Q.

The sun delivers ${10}^3{\mathrm{Wm}}^{-2}$ of electromagnetic flux on the earths surface. The total power that is incident on a roof of dimensions $6\mathrm{m}\times 30\mathrm{m}$, is

1. $1.8\times {10}^5\mathrm{W}$

2. $7.2\times {10}^5\mathrm{W}$

3. $0.9\times {10}^5\mathrm{W}$

4. $4.5\times {10}^5\mathrm{W}$

Q.

Blue colour is a primary colour but yellow colour is a secondary colour.

1. True
2. False