Electromagnetic spectrum

The terminology of different parts of the electromagnetic spectrum is given in the text. Use the formula E = h ν (for energy of a quantum of radiation: photon) and obtain the photon energy in units of eV for different parts of the electromagnetic spectrum. In what way are the different scales of photon energies that you obtain related to the sources of electromagnetic radiation?

(a) Give a list of at least five radiations, in the order of their increasing wavelength, which make up the complete electromagnetic spectrum. (b) Name the radiation mentioned by you in part (a) which has the highest penetrating power.

(a) Where should an object be kept on the principal axis of a convex lens of focal length 20 cm in order to get an image, which is double the size of the object? (b) Name the part of the electromagnetic spectrum which is (i) Suitable for radar systems used in aircraft navigation. (ii) Produced by bombarding a metal target with high electrons.

Identify the constituent radiations of electromagnetic spectrum which (1). Is absorbed by ozone layer in the atmosphere (2). Is produced by bombarding a metal target by high speed electrons (3). Is used in satellite communication (4). has wavelength range between 400 nm to 700 nm.

In a hydrogen atom, an electron undergoes transition from an energy level with n= 4 to an energy level with n= 2. Calculate the wavelength of the spectral line thus obtained. In which region of electromagnetic spectrum this line would be observed and what would be its colour?

(i) Why the thin ozone layer on the top of the atmosphere is crucial for human survival ? Identify in which part of electromagnetic spectrum does this radiation belong and write an important application of this radiation. (ii) Why are infrared waves referred to as heat waves ? How are they produced ? What role do they play in maintaining earth.s warmth through the greenhouse effect ?

Given below are some famous numbers associated with electromagnetic radiations in different contexts in physics. State the part of the electromagnetic spectrum to which each belongs. (a) 21 cm (wavelength emitted by atomic hydrogen in interstellar space). (b) 1057 MHz (frequency of radiation arising from two close energy levels in hydrogen, known as Lamb shift). (c) 2.7 K [temperature associated with the isotropic radiation filling all space-thought to be a relic of the ‘big-bang’ origin of the universe]. (d) 5890 hatA-5896hatA (double lines of sodium] (e) 14.4keV energy of a particular transition in .^(57)Fe nucleus associated with a famour high resolution spectroscopic method (mossbauer spectroscopy).

Choose the correct option relating wavelengths of different parts of electromagnetic wave spectrum.

Electromagnetic waves are

Electromagnetic induction