Work, Energy and Power-Work-Energy Theorem (KVPY Stream SB-SX (Class 12 & 1st Year BSC) Physics): Questions 1 - 3 of 4

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Question number: 1

» Work, Energy and Power » Work-Energy Theorem

Appeared in Year: 2011

MCQ▾

Question

Two plates each of the mass m are connected by a massless spring as shown.

 Two plates connected by spring

Two Plates Connected by Spring

In figure two plates each of the mass m are connected by a massless spring as shown.

A weight W is put on the upper plate which compresses the spring further. When W is removed, the entire assembly jumps up. The minimum weight W needed for the assembly to jump up when the weight is removed is just more than –

Choices

Choice (4) Response
a.

2mg

b.

4mg

c.

mg

d.

3mg

Question number: 2

» Work, Energy and Power » Work-Energy Theorem

Appeared in Year: 2012

MCQ▾

Question

In one model of the election, the mass of electron me is thought to be a uniformly charged shell of radius R and total charge e, whose electrostatic energy E is equivalent to its mass me via Einstein’s mass energy relation E = mec2. In this model, R is approximately – (me = 9.1 × 10-31kg, c = 3 × 108 ms-1, 14πϵ0=9×109Faradsm1, magnitude of the electron charge = 1.6 × 10-19 C)

Choices

Choice (4) Response
a.

1.4×1015m

b.

2.8×1035m

c.

2×1013m

d.

5.3×1011m

Question number: 3

» Work, Energy and Power » Work-Energy Theorem

Appeared in Year: 2012

MCQ▾

Question

A stream of photons having energy 3 eV each impinges on a potassium surface. The work function of potassium is 2.3 eV. The emerging photo-electrons are slowed down by a copper plate placed 5 mm away. If the potential difference between the two metal plates is 1V, the maximum distance the electrons can move away from the potassium surface before being turned back is

Choices

Choice (4) Response
a.

3.5 mm

b.

5.0 mm

c.

1.5 mm

d.

2.5 mm

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