Atoms and Nuclei (KVPY (Kishore Vaigyanik Protsahan Yojana) Stream SB-SX (Class 12 & 1st Year B.Sc.) Physics): Questions 9 - 12 of 14

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Question number: 9

» Atoms and Nuclei » Energy Levels

MCQ▾

Question

The wavelength of the first Balmer line caused by a transition from the n = 4 level to the n = 2 level in hydrogen is λ1. The wavelength of the line caused by an electronic transition from n = 7 to n = 3 is –

Choices

Choice (4) Response

a.

b.

c.

d.

Question number: 10

» Atoms and Nuclei » Half Life and Mean Life

MCQ▾

Question

A nucleus has a half – life of 45 minutes. At 2: 45 PM its decay rate was measured as 160,000 counts/sec. What will be the decay rate at 5: 45 PM?

Choices

Choice (4) Response

a.

b.

c.

d.

Question number: 11

» Atoms and Nuclei » Binding Energy Per Nucleon

Appeared in Year: 2014

MCQ▾

Question

A solid sphere slipping about a horizontal axis with an angular velocity 𝜔 is placed on a horizontal surface. Subsequently it rolls without slipping with an angular velocity of –

Choices

Choice (4) Response

a.

b.

c.

d.

ω

Question number: 12

» Atoms and Nuclei » Bohr Model

Appeared in Year: 2015

MCQ▾

Question

A donor atom in a semiconductor has a loosely bound electron. The orbit of this electron is considerably affected by the semiconductor material but behaves in many ways like an electron orbiting a hydrogen nucleus. Given that the electron has an effective mass of 0.07me, (where me is mass of the electron) and the space in which it moves has a permittivity, then the radius of the electron’s lowermost energy orbit will be close to (The Bohr radius of the hydrogen atom is 0.53 Å)

Choices

Choice (4) Response

a.

10 Å

b.

100 Å

c.

243 Å

d.

0.53 Å

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