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Ashok0210

Asked: March 21, 2021In: Class 12 Physics

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 A º – 5896 A º [double lines of sodium] (e) 14.4 keV [energy of a particular transition in 57Fe nucleus associated with a famous high resolution spectroscopic method (Mossbauer spectroscopy)].

Class 12 Physics CBSE and UP Board Electromagnetic Waves Chapter-8 Exercise 8.14 NCERT Solutions for Class 12 Physics Chapter 8 Question 14 Additional Exercise

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

About 5% of the power of a 100 W light bulb is converted to visible radiation. What is the average intensity of visible radiation (a) at a distance of 1 m from the bulb? (b) at a distance of 10 m? Assume that the radiation is emitted isotropically and neglect reflection.

Class 12 Physics CBSE and UP Board Electromagnetic Waves Chapter-8 Exercise 8.12 NCERT Solutions for Class 12 Physics Chapter 8 Question 12 Additional Exercise

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

Suppose that the electric field part of an electromagnetic wave in vacuum is E = {(3.1N/C) cos [(1.8 rad/m)y + (5.4 x 10⁶ rad/s)t]} l. (a) What is the direction of propagation? (b) What is the wavelength λ? (c) What is the frequency ν? (d) What is the amplitude of the magnetic field part of the wave? (e) Write an expression for the magnetic field part of the wave.

Class 12 Physics CBSE and UP Board Electromagnetic Waves Chapter-8 Exercise 8.11 NCERT Solutions for Class 12 Physics Chapter 8 Question 11 Additional Exercise

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of 2.0 x 10¹⁰ Hz and amplitude 48 V m⁻¹. (a) What is the wavelength of the wave? (b) What is the amplitude of the oscillating magnetic field? (c) Show that the average energy density of the E field equals the average energy density of the B field, [c = 3 x 10⁸m s⁻¹.]

Class 12 Physics CBSE and UP Board Electromagnetic Waves Chapter-8 Exercise 8.10 NCERT Solutions for Class 12 Physics Chapter 8 Question 10

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

The terminology of different parts of the electromagnetic spectrum is given in the text. Use the formula E = hν (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?

Class 12 Physics CBSE and UP Board Electromagnetic Waves Chapter-8 Exercise 8.9 NCERT Solutions for Class 12 Physics Chapter 8 Question 9

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About 5% of the power of a 100 W light bulb is converted to visible radiation. What is the average intensity of visible radiation (a) at a distance of 1 m from the bulb? (b) at a distance of 10 m? Assume that the radiation is emitted isotropically and neglect reflection.

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