Science (English Medium) इयत्ता १२ - CBSE Important Questions

Identify the part of the electromagnetic spectrum which is:

produced by bombarding a metal target by high speed electrons.

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.

To which part of electromagnetic spectrum does a wave of frequency 3 × 10¹³ Hz belong?

To which part of the electromagnetic spectrum does a wave of frequency 5 × 10¹⁹ Hz belong?

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.