Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 14

HARD

JEE Advanced

IMPORTANT

Earn 100

The monochromatic light of frequency $3 \times 10^{14} Hz$ , which is produced by a laser, emits the power of $3 \times 10^{- 3} W$ . Find, how many photons are emitted per second?

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Important Questions on Modern Physics

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JEE Advanced

IMPORTANT

Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 15

The ratio of radii of nuclei of two atoms of element of atomic mass numbers

27

and

64

is

EASY

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IMPORTANT

Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 16

The value of Rydberg constant is

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Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 17

The total energy of an electron in

4^{th}

orbit of the hydrogen atom is

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IMPORTANT

Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 18

The work functions of silver and sodium are

4.6

and

2.3 eV

, respectively. The ratio of the slope of the stopping potential versus frequency plot for silver to that of sodium is

EASY

JEE Advanced

IMPORTANT

Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 19

An

α

-particle and a proton are accelerated from rest by a potential difference of

100 V

. After this, their de-Broglie wavelengths are

λ_{α}

and

λ_{p}

, respectively. The ratio

\frac{λ_{p}}{λ_{α}}

to the nearest integer is

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IMPORTANT

Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 20

The correct statement is

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IMPORTANT

Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 21

The kinetic energy (in $KeV$ ) of the $α$ - particle, when the nucleus ${}_{84}^{210}{Po}$ at rest undergoes $α$ -decay, is

EASY

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IMPORTANT

Complete Study Pack for Engineering Entrances Objective Physics Vol 2>Chapter 9 - Modern Physics>Objective Problems [Level 2]>Q 22

The anode voltage of a photocell is kept fixed. The wavelength

λ

of the light falling on the cathode is gradually changed. The plate current

I

of photocell varies as follows: