Physics Questions

Q:

A boy sitting in a train moving with a uniform velocity drops a coin outside. A man standing outside the train will find the trajectory of the coin to be

A) a parabola B) a circle
C) a horizontal straight line D) a vertical straight line
 
Answer & Explanation Answer: A) a parabola

Explanation:

Parabola, because when the coin is dropped at a particular point, it has the same velocity as the running train. So by Newton's first law, it continues its motion horizontally with that velocity. But then, it is also pulled down by earth's gravity continuously. In this situation its horizontal motion gives way to the parabolic motion until it reaches the ground.

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Q:

RADAR is used for

A) detecting and locating the position of objects such as Aeroplanes B) locating submerged submarines
C) locating geostationary satellites D) receiving a signals in a radio receiver
 
Answer & Explanation Answer: A) detecting and locating the position of objects such as Aeroplanes

Explanation:

RADAR - RAdio Detection And Ranging.

A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. 

 

Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain.

 

Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the object's location and speed.

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Q:

Solids have definite shapes.This is because

A) the forces of cohesion of the molecules within are very much less in them B) the forces of cohesion are very large
C) the forces of adhesion are large D) the forces of adhesion are less
 
Answer & Explanation Answer: B) the forces of cohesion are very large

Explanation:

Cohesion refers to attraction between molecules of the same kind while adhesion refers to attraction between different kinds of molecules

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Q:

Which planet has the lowest density?

A) Earth B) Jupiter
C) Saturn D) Neptune
 
Answer & Explanation Answer: C) Saturn

Explanation:

Saturn, the solar system's second largest planet that takes the prize for least dense. It's less dense than water, which has led many people to postulate that it would float.

However, even if it somehow found its way to a body of water large and deep enough to contain it, Saturn would break apart and its rocky core would sink.

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Q:

Materials that allow electricity to flow are called

A) Insulators B) Conductors
C) Electron flows D) Stimulators
 
Answer & Explanation Answer: B) Conductors

Explanation:

Materials that allow electricity to flow are called electrical conductors and that materials which does not allow electricity to flow are called Insulators.

materials_that_allow_electricity_to_flow_are_called1535107310.png image

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Q:

The Length of the Day is determined in

A) length of the hours B) length of the year
C) astronomical units D) solar terms
 
Answer & Explanation Answer: C) astronomical units

Explanation:

The Length of the Day is determined in Astronomical Units.

The length of a day corresponds to the time the Earth takes to turn around on its axis, which is approximately 24 hours. But it's not exactly 24 hours. 

This phenomenon is due to tides raised by the Moon which slow Earth's rotation. Because of the way the second is defined, the mean length of a day is now about 86 400.002 seconds, and is increasing by about 1.7 milliseconds per century.

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Q:

Which process allows water to enter the atmosphere?

A) Transpiration B) Respiration
C) Condensation D) Evaporation
 
Answer & Explanation Answer: D) Evaporation

Explanation:

Evaporation is the process that allows water to enter into the atmosphere.

Sunlight turns liquid water into water vapor which then rises higher into the atmosphere and forms into clouds.

 

Plants, too, help water get into the atmosphere through a process called transpiration.

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Q:

Electric current is measured by which instrument?

A) voltmeter B) ammeter
C) barometer D) sinometer
 
Answer & Explanation Answer: B) ammeter

Explanation:

Electric current is measured by the instrument called ammeter. As current in a circuit is measured in amperes, the instrument used is called as ammeter.

Electric_current_is_measured_by_which_instrument1555505098.jpg image

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