Physics - Comprehensive Mock Test 3

Question 21 Medium

A device which is used to limit the current in an electrical circuit is called a

A) Grid B) Fuse C) Hub D) Conductor

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Solution Breakdown:

A fuse places a limit on the amount of current that can be drawn by an electric circuit by opening (blowing or melting) when the current exceeds a preset limit. This protects the circuit and the surroundings from fire or damage in the case of an overload or short circuit.

Question 22 Easy

The first model of atom was proposed by

A) Hans Geiger B) Rutherford C) J.J. Thomson D) E. Goldstein

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Solution Breakdown:

No Details

Question 23 Hard

Water is flowing through a tube of non-uniform cross-section. Ratio of the radius at entry and exit end of the pipe is 3 : 2. Then the ratio of velocities at entry and exit of liquid is

A) 4 : 9 B) 9 : 4 C) 8 : 27 D) 1 : 1

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Solution Breakdown:

No Details

Question 24 Medium

If you set up the seventh harmonic on a string fixed at both ends, how many nodes and antinodes are set up in it

A) 8, 7 B) 7, 7 C) 8, 9 D) 9, 8

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Solution Breakdown:

No Details

Question 25 Hard

To break a wire of one meter length, minimum 40 kg wt. is required. Then the wire of the same material of double radius and 6 m length will require breaking weight

A) 80 kg-wt B) 240 kg-wt C) 200 kg-wt D) 160 kg-wt

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Solution Breakdown:

No Details

Question 26 Hard

The escape velocity of a body from the earth is u. What is the escape velocity from a planet whose mass and radius are twice those of the earth

A) 2u B) u C) 4u D) 16u

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Solution Breakdown:

No Details

Question 27 Hard

The diameter of rain-drop is 0.02 cm. If surface tension of water be 72 × 10-³ newton per meter, then the pressure difference of external and internal surfaces of the drop will be

A) 1.44 × 10⁴ dyne – cm⁻² B) 1.44 × 10⁴ newton – m⁻² C) 1.44 × 10³ dyne – cm⁻² D) 1.44 × 10⁵ newton – m⁻²

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Solution Breakdown:

No Details

Question 28 Medium

If the mean free path of atoms is doubled, then the pressure of gas will become

A) P/4 B) P/2 C) P/8 D) P

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Solution Breakdown:

No Details

Question 29 Hard

Two bodies having same mass 20 kg are moving in opposite directions, one with a velocity of 10 m/s and the other with 5 m/s. If they collide and move as one body, the velocity of the combination is

A) 2.5 m/s B) 5 m/s C) 7.5 m/s D) 15 m/s

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Solution Breakdown:

No Details

Question 30 Easy

Which of the following is a self adjusting force

A) Static friction B) Rolling friction C) Sliding friction D) Dynamic friction

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Solution Breakdown:

No Details