Science (English Medium) Class 12 - CBSE Important Questions for Physics

To which part of the electromagnetic spectrum does a wave of frequency 5 × 10¹¹ Hz belong?

The small ozone layer on top of the stratosphere is crucial for human survival. Why?

The charging current for a capacitor is 0.25 A.  What is the displacement current across its plates?

Name the em waves which are used for the treatment of certain forms of cancer. Write their frequency range ?

Name the em waves which are produced during radioactive decay of a nucleus. Write their frequency range ?

Which part of electromagnetic spectrum is used in radar systems?

Write the range of the wavelength of the following electromagnetic radiations:
(a) Infrared rays
(b) Ultraviolet rays
(c) γ -rays

Write one use of each of the above.

Define the term "Intensity" in the photon picture of electromagnetic radiation. 

Identify the part of the electromagnetic spectrum used in (i) radar and (ii) eye surgery. Write their frequency range.

Identify the part of the electromagnetic spectrum used in
(i) radar and
(ii) eye surgery. Write their frequency range.

Name the radiation of the electromagnetic spectrum which is used for the following:

Radar and Give the frequency range.

Name the radiation of the electromagnetic spectrum which is used for the following:

To photograph internal parts of the human body and Give the frequency range

Name the radiation of the electromagnetic spectrum which is used for the following:

For taking photographs of the sky during the night and foggy conditions . Give the frequency range

Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves.

If the Earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now? Explain.

An e.m. wave exerts pressure on the surface on which it is incident. Justify.

Electromagnetic waves with wavelength

1. λ₁ is suitable for radar systems used in aircraft navigation.
2. λ₂ is used to kill germs in water purifiers.
3. λ₃ is used to improve visibility in runways during fog and mist conditions.

Identify and name the part of the electromagnetic spectrum to which these radiations belong. Also arrange these wavelengths in ascending order of their magnitude.

Identify the electromagnetic wave whose wavelength range is from about 10^-12 m to about 10^-8 m. Write one use of this.

Identify the electromagnetic wave whose wavelength range is from about 10^-3 m to about 10^-1 m. Write one use of this.

Choose the correct option related to wavelengths (λ) of different parts of the electromagnetic spectrum.