A prism is made up of material of refractive index . The angle of prism is A. If the angle of minimum deviation is equal to the angle of the prism, then the value of A is

1.  30°

2.  45°

3.  60°

4.  75°

Subtopic: Prisms |

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Q10:

The half-life of a radioactive substance is 10 days. This means that

1. The substance completely disintegrates in 20 days
2. The substance completely disintegrates in 40 days
3. 1/8 part of the mass of the substance will be left intact at the end of 40 days
4. 7/8 part of the mass of the substance disintegrates in 30 days

Subtopic: Radioactivity (OLD NCERT) |

From NCERT

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Q11:

A source and an observer are moving towards each other with a speed equal to v/2, where v is the speed of sound. The source is emitting sound of frequency n. The frequency heard by one observer will be

1. zero

2. n

3.

4. 3n

Subtopic: Doppler's Effect (OLD NCERT) |

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Q12:

Velocity of sound waves in air is 330 m/s. For a particular sound in air, a path difference of 40 cm is equivalent to phase difference of 1.6π. The frequency of the wave is

1.  165 Hz
2.  150 Hz
3.  660 Hz
4.  330 Hz

Subtopic: Speed of Sound |

59%

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Q13:

The power factor of the circuit shown in the figure is

1. 0.2

2. 0.4

3. 0.8

4. 0.6

Subtopic: Different Types of AC Circuits |

64%

From NCERT

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Q14:

A particle is executing linear simple harmonic motion of amplitude A. What fraction of the total energy is kinetic when the displacement is half the amplitude

1.

2.

3.

4.

Subtopic: Energy of SHM |

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Q17:

When 20 J of work was done on the gas, 40 J of heat energy was released. If the initial internal energy of the gas was 70 J, what is the final internal energy?

1. 50 J

2. -150 J

3. 90 J

4. 110 J