KVPY Stream-SA (Class 11) Physics: Questions 201 - 204 of 252

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Question number: 201

» Kinematics » Relative Velocity

MCQ▾

Question

A train of length l (180 m) is going towards north directional constant speed v1=16 m/s. A parrot flies at a constant speed of v2 = 4 m/s towards south parallel to be railway track. The time taken by the parrot to cross the train is –

Choices

Choice (4) Response

a.

7 s

b.

3 s

c.

9 s

d.

5 s

Question number: 202

» Atoms and Nuclei » Isotopes

MCQ▾

Question

The isotopes 238U and 235U occur in nature in the ratio 150: 1. Assuming that at the time of earth formation they were present in equal amount; make an estimation of the age of the earth. The half-lives of 238U and 235U are 5.7×109yr and 6.3×108yr respectively.

[log10150=2.1761&log102=0.3010]

Choices

Choice (4) Response

a.

5.12×108years

b.

4.78×108years

c.

5.12×109years

d.

4.78×109years

Question number: 203

» Work, Energy and Power » Conservative and Non-Conservative Forces

MCQ▾

Question

The height of a waterfall is 75 m, If the water at the bottom of the fall is at rest. Calculate the difference between temperature of water at the top and bottom of the fall (specific heat of water =4.2103Jkg0C and g=9.8ms2 ).

Choices

Choice (4) Response

a.

0.175 0C

b.

0.97 0C

c.

0.126 0C

d.

0.117 0C

Question number: 204

» Experimental Skills » Transistor

MCQ▾

Question

The transfer ratio β of a transistor is 60. The input resistance of the transistor when used in the common-emitter configuration is 2 KΩ. The peak value of the collector a. c. current for an a. c. input voltage of 0.05 V peak is –

Choices

Choice (4) Response

a.

1.5mA

b.

3mA

c.

2.5mA

d.

2mA

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