Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 157

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Photons are not deflected in electric and magnetic field as they are

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Important Questions on Electrons and Photons

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 158

The momentum of a photon is

3.3 \times 10^{- 29} kg - m s^{- 1} .

Its frequency will be

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 159

A photon of wavelength

4400 \overset{\circ}{A}

is passing through the vacuum. The effective mass and momentum of the photon are respectively

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 160

A

200 W

sodium street lamp emits yellow light of wavelength

0.6 μm

. Assuming it to be

25 %

efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 161

Assertion: Photons can exist at rest.

Reason: Rest mass is given as , $m_{0} = m \times \sqrt{1 - \frac{v^{2}}{c^{2}}}$

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 162

Eye of an experimenter detects the green light

(λ = 4000 \overset{\circ}{A})

at

5 \times 10^{4}

Photons per square metre per second and ear can detect

10^{- 13}

W m^{- 2}

. The eye is sensitive as a power detector in comparison to the ear by a factor of

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 163

If

h

is the Planck's constant, then the momentum of a photon of wavelength

0.01 Å

is

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 164

If the wavelength of X-ray photon is

0.01 Å

, then its momentum(in

kg m s^{- 1}

) is

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 165

The energy

E

and momentum

p

of photon is given by

E = h ν

and

p = \frac{h}{λ},

the velocity of photon will be-