Physics - Mock Test 24

Question 231

Decibel is the unit of

A) intensity of light B) X-ray radiation capacity C) sound loudness D) energy of radiation

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Question 232

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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Question 233

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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Question 234

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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Question 235

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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Question 236

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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Question 237

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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Question 238

A ball of mass 0.1 kg coming with speed 30 m/s strikes with a bat and returns in opposite direction with speed 40 m/s, then the impulse exerted on the ball is : <br>(Taking final velocity as positive)

A) 7 N–s B) 1 N–s C) 3 N–s D) 4 N–s

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Question 239

The force acting on the bullet when it moves through the air towards a target is:

A) Force due to the gun B) Gravitational force alone C) Gravitational force and frictional force. D) Frictional force alone

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Question 240

What is the unit of the physical quantity "Inductance"?

A) weber B) farad C) henry D) tesla

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