A
it can pass through all materials without absorption
B
it is readily absorbed by water and other molecules, increasing their thermal motion
C
it has the shortest wavelength in the spectrum
D
it ionises the molecules of air

Q45. AI-generated practice Single-correct MCQ Medium

The ozone layer in the upper atmosphere protects life on Earth mainly by absorbing:

A
ultraviolet radiation
B
infrared radiation
C
visible light
D
radio waves

Q46. AI-generated practice Single-correct MCQ Medium

X-rays used in medical imaging are commonly produced by:

A
heating a filament to a red glow
B
radioactive decay of nuclei only
C
oscillating charges in an LC circuit
D
bombarding a metal target with high-energy electrons

Q47. AI-generated practice Single-correct MCQ Hard

Visible light has wavelengths from about 400 nm to 700 nm. The corresponding range of frequencies is about (c = 3 × 10⁸ m/s):

A1.2 × 10² Hz to 2.1 × 10² Hz
B4.3 × 10¹⁴ Hz to 7.5 × 10¹⁴ Hz
C4.3 × 10¹¹ Hz to 7.5 × 10¹¹ Hz
D4 × 10¹⁴ Hz to 7 × 10¹⁴ Hz

Q48. AI-generated practice Single-correct MCQ Easy

Television and air-conditioner remote controls usually work using:

A
γ-rays
B
ultraviolet radiation
C
X-rays
D
infrared radiation

Q49. AI-generated practice Single-correct MCQ Medium

An electromagnetic wave has a wavelength of 3 cm in vacuum. Its frequency and the region of the spectrum it belongs to are (c = 3 × 10⁸ m/s):

A
1 GHz, infrared
B
10 GHz, radio waves (AM band)
C
100 GHz, visible light
D
10 GHz, microwaves

Q50. AI-generated practice Single-correct MCQ Hard

The energy of an X-ray photon of wavelength 0.1 nm is about (hc = 1240 eV nm):

A
12.4 keV
B
124 eV
C
1.24 keV
D
124 keV

Q51. AI-generated practice Single-correct MCQ Medium

γ-rays are emitted mainly during:

A
molecular vibrations
B
oscillations of electrons in an antenna
C
transitions of atomic nuclei from excited states
D
transitions of outer electrons in atoms

Q52. AI-generated practice Single-correct MCQ Medium

Which electromagnetic radiation is used to sterilise surgical instruments and to purify water?

A
infrared rays
B
microwaves
C
ultraviolet rays
D
radio waves

Q53. AI-generated practice Single-correct MCQ Easy

Among visible light, ultraviolet, infrared and microwaves, the radiation with the highest frequency is:

A
infrared
B
microwaves
C
ultraviolet
D
visible light

Q54. AI-generated practice Single-correct MCQ Hard

Radio waves (A), X-rays (B), visible light (C) and microwaves (D) arranged in increasing order of frequency are:

A
A, C, D, B
B
A, D, C, B
C
B, C, D, A
D
D, A, C, B

Q55. AI-generated practice Numerical value Easy

Find the frequency of yellow light of wavelength 600 nm in vacuum, in units of 10¹⁴ Hz. (c = 3 × 10⁸ m/s)

Q56. AI-generated practice Numerical value Medium

Find the wavelength in metre of an AM radio wave of frequency 1 MHz. (c = 3 × 10⁸ m/s)

Q57. AI-generated practice Numerical value Medium

Find the energy (in eV) of a photon of red light of wavelength 620 nm. (hc = 1240 eV nm)

Q58. AI-generated practice Numerical value Hard

A microwave oven works at a frequency of 2.45 GHz. Find the wavelength of these microwaves in cm, to the nearest integer. (c = 3 × 10⁸ m/s)

Q59. AI-generated practice Assertion–Reason Medium

Assertion (A): The ozone layer is crucial for the survival of life on Earth.
Reason (R): Ultraviolet rays have shorter wavelengths than visible light.

A
Both A and R are true and R is the correct explanation of A
B
Both A and R are true but R is not the correct explanation of A
C
A is true but R is false
D
A is false but R is true

Q60. AI-generated practice Assertion–Reason Hard

Assertion (A): X-rays have longer wavelengths than ultraviolet rays.
Reason (R): X-rays are produced when fast-moving electrons strike a metal target.

A
Both A and R are true and R is the correct explanation of A
B
Both A and R are true but R is not the correct explanation of A
C
A is true but R is false
D
A is false but R is true