KVPY Stream SB-SX (Class 12 & 1st Year BSC) Physics: Questions 163 - 165 of 250

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Question number: 163

» Properties of Solids & Liquids » Young's Modulus

Appeared in Year: 2015

MCQ▾

Question

A horizontal steel railroad track has a length of 100 m when the temperature is 250 C. The track is constrained from expanding or bending. The stress on the track on a hot summer day, when the temperature is 400 C, is –

(Note: the linear coefficient of thermal expansion for steel is 1.1×105/0C and the Young’s modulus of steel is 2×1011Pa )

Choices

Choice (4) Response

a.

8.8×107Pa

b.

5.5×107Pa

c.

3.3×107Pa

d.

6.6×107Pa

Question number: 164

» Properties of Solids & Liquids » Temperature

Appeared in Year: 2015

MCQ▾

Question

A closed bottle containing water at 300 C is open on the surface of the moon. Then,

Choices

Choice (4) Response

a.

The water will come out as a spherical ball.

b.

The water will freeze.

c.

The water will boil.

d.

The water will decompose into hydrogen and oxygen.

Question number: 165

» Electrostatics » Electrostatic Potential Energy

Appeared in Year: 2014

MCQ▾

Question

Consider a spherical shell of radius R with a total charge + Q uniformly spread on its surface (center of the shell lies at the origin x = 0). Two point charge, +q and – q are brought, one after the other, from far away and placed at x=a2 and x=+a2(a<R) , respectively. Magnitude of the work done in this process is

Choices

Choice (4) Response

a.

q24πε0a

b.

Qq4πε0a

c.

(Q+q)24πε0a

d.

zero

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