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Test : Physics - 4

20 Questions MCQ Test NDA (National Defence Academy) Mock Test Series | Test : Physics - 4

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This mock test of Test : Physics - 4 for Defence helps you for every Defence entrance exam. This contains 20 Multiple Choice Questions for Defence Test : Physics - 4 (mcq) to study with solutions a complete question bank. The solved questions answers in this Test : Physics - 4 quiz give you a good mix of easy questions and tough questions. Defence students definitely take this Test : Physics - 4 exercise for a better result in the exam. You can find other Test : Physics - 4 extra questions, long questions & short questions for Defence on EduRev as well by searching above.
QUESTION: 1

On which principle does the hydraulic lift works?

Solution:

Pascal's Law states that pressure that is applied to an enclosed fluid is transmitted equally to all other points. A hydraulic pump is a water pump that uses the kinetic energy of flowing water to force a small fraction of that water to a reservoir at a higher level. The hydraulic lift works because of Pascal’s law. If force is put on(according to Pascal’s Law), that force should be entirely felt on all points throughout the liquid.

QUESTION: 2

The coil wire in the electric room heater or electric cooking heater is called __________.

Solution:

The coil wire is heating element in electric room heater or electric cooking heater to converts electricity into heat through the process of resistive or Joule heating. Electric current passing through the element encounters resistance, resulting in heating of the element.

QUESTION: 3

Energy in the form of heat is wasted when a machine is operated. This heat is generated due to ___________.

Solution:

Energy in the form of heat is wasted when a machine is operated. This heat is generated due to Friction between two parts.

QUESTION: 4

The incident ray, the _________ at the point of incidence and the reflected ray all lie in the same plane.

Solution:

The law of reflection states that the incident ray, the reflected ray, and the normal at the point of incidence all lie in the same plane.

QUESTION: 5

Seismometer was invented by -

Solution:

A Seismometer is an instrument that measures motion of the ground, caused by, for example, an earthquake, a volcanic eruption, or the use of explosives. It was invented by Italian scientist Luigi Palmieri.

QUESTION: 6

For every action, there is an equal and opposite reaction, is Newton's

Solution:

Newton third law states that for every action there is an equal and opposite reaction.

QUESTION: 7

Which among the following is false about displacement?

Solution:

A Displacement is a vector whose length is the shortest distance from the initial to the final position of a point P. It quantifies both the distance and direction of an imaginary motion along a straight line from the initial position to the final position of the point.

QUESTION: 8

An object at rest will remain at rest and an object in motion will remain in motion until and unless it is acted upon by an external force. This is Newton's

Solution:

Newton's First Law of Motion states that a body at rest will remain at rest unless an outside force acts on it, and a body in motion at a constant velocity will remain in motion in a straight line unless acted upon by an outside force.

QUESTION: 9

What will happen if an object is dropped from a height and there is no air resistance?

Solution:

When an Object is dropped from height and when there is no air resistance the speed of object will increase.

QUESTION: 10

If ice floating on water in a vessel melts, the water level in the vessel _______.

Solution:

The water level remains the same when the ice cube melts. A floating object displaces an amount of water equal to its own weight. Since water expands when it freezes, one ounce of frozen water has a larger volume than one ounce of liquid water.

QUESTION: 11

If in a motion, the axis of the rotation does not pass through the object, then the motion is called ________.

Solution:

The Orbital Motion Interactive is simulates the elliptical motion of a satellite around a central body. In this type of motion axis of the rotation does not pass through the object.

QUESTION: 12

What are the two kinds of Rotatory motion?

Solution:

Spin and Orbital motion are the two kinds of Rotatory motion.

QUESTION: 13

Rate of change of momentum is -

Solution:

The rate of change of momentum of an object is directly proportional to the resultant force applied and is in the direction of the resultant force. The resultant force is equal to the rate of change of momentum.

QUESTION: 14

What did J B Dunlop invent?

Solution:

Scottish inventor and veterinary surgeon John Boyd Dunlop developed the pneumatic (air-filled) rubber tire. He was one of the founders of the rubber company that bore his name, Dunlop Pneumatic Tyre Company. In 1888, Dunlop patented his pneumatic tyre.

QUESTION: 15

When net torque is zero, __________ will be constant.

Solution:

When net torque is zero, angular momentum will be constant.

QUESTION: 16

Newton's first law is also known as _______.

Solution:

Newton's first law of motion is also known as the law of inertia.Newton's First Law of Motion states, "A body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by an external force."

QUESTION: 17

With reference to gravity, what is G called?

Solution:

The gravitational constant, symbolized G , is a physical constant that appears in the equation for Newton's law of gravitation. This is different from ‘g’ which is denotes the acceleration due to gravity.

QUESTION: 18

In a projectile motion, a large angle with the horizontal produces ______.

Solution:

In a projectile motion, a large angle with the horizontal produces high trajectory.

QUESTION: 19

A device which converts electrical energy into mechanical energy is-

Solution:

Electric motor is a device which converts electrical energy into mechanical energy. Electric motors involve rotating coils of wire which are driven by the magnetic force exerted by a magnetic field or an electric current.

QUESTION: 20

The force of friction between two surfaces will increase if:

Solution:

The force of friction between two surfaces will increase if the two surfaces are pressed harder.