Consider the following types of electromagnetic radiation: radiowaves, infra-red, vissible light. Which of the following statements are correct?
(i) Only radiowaves can be used to transmite audio information.
(ii) Only infrared radiation is emitted by very hot object.
(iii) Only visible light can be detect by humans.

Options

A. only (i) is correct
B. only (ii) is correct
C. only (iii) is correct
D. None of the above is correct.

Answer

d

Explanation

(i) Audio information can be transmitted in the
from of the optical wave through optical fibres.
(ii) very hot objects emit not only infrared
radiation but also emit visible radiation.
(iii) Humans can detect infrared radiations by
feeling the heat on the portion of body exposed by
radiation.
Therefore, all the given statements are not
completely correct. Hence the option(d) is
correct.