# GK Questions: General Science(Physics) – Set 26

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Welcome to Online General Knowledge section in Affairs cloud, which is important for SSC, UPSC, Civil Service exams and other competitive exams. We have created Some questions related to General Science(Physics) !!!

1. A magnetic needle in compass always direct in which direction ?
1.North – South
2.South – North
3.East – West
4.West – East
5.None of these
Explanation :
In Magnetic compass, a magnetic needle which always direct in North-South (N-S) direction.

2. Static friction is _____________ Kinetic friction
1.same as
2.Lesser than
3.Equal to
4.Greater than
5.None of these
Explanation :
Static friction is greater than kinetic friction because of irregularities between thestatic object and the surface upon which it rests. The irregularities mesh together making it more difficult to start movement than to keep the object in motion

3. Fleming’s left-hand rule is applicable for which of the following ?
1.Electric Generators
2.Electric motors
3.Electric Fans
4.Electric Lights
5.None of these
Explanation :
In an electric motor, the electric current and magnetic field exist (which are the causes), and they lead to the force that creates the motion (which is the effect), and so the left hand rule is used.

4. X-rays travel in_________________and a beam of X-rays diverges from its source.
1.Opposite direction
2.Can’t say
3.Straight line
4.Circle
5.None of these
Explanation :
X-rays are electromagnetic waves with wavelength range 0.1 A-100 A.X-rays were discovered by Roentgen and X-rays travels in straight line.

5. In ophthalmoscope which mirror is used to examine eye, ear, nose by doctors.
1.Convex mirror
2.Spherical Mirrors
3.Plane mirrors
4.Concave mirror
5.None of these
Explanation :
In ophthalmoscope concave mirror is used to examine eye, ear, nose by doctors. Concave mirror is used in a shaving mirror and also used as a reflector for the head lights of a vehicle, search light

6. The density of sea water is _________  the density of fresh water
1.Lesser than
2.Equal to
3.Greater than
4.Can’t say
5.None of these
Explanation :
Salt water is denser than fresh, salt water provides more buoyancy there is even differences from the pacific ocean and the Atlantic

7. The density of pure water is _________________
1.100 kg/m3
2.1000 kg/m3
3.2000 kg/m3
4.1500 kg/m3
5.None of these
Explanation :
The density of pure water is 1000 kg/m3. Ocean water is more dense because of the salt in it. Density of ocean water at the sea surface is about 1027 kg/m3.

8. The Upthrust is a which type of force ?
1.Upward force
2.Downward force
3.Frictional Force.
4.Applied force
5.None of these
Explanation :
Upthrust is defined as the upward force on the object provided by the liquid because the object has “displaced” some of the fluid.

9. Thermionic emission occurs when the metal is _______________
1.Heated at very high temperature
2.Heated at high temperature
3.Cooled at very low temperature
4.All of these
5.None of these
Answer – 1.Heated at very high temperature
Explanation :
The process by which free electrons are emitted from the surface of a metal when external heat energy is applied is called thermionic emission. Thermionic emission occurs in metals that are heated to a very high temperature.

10. Which rule is applicable for Generators ?
1.Fleming’s right-hand rule
2.Centrifugal force
3.Kirchhoff’s circuit laws
4.Fleming’s right-hand rule
5.None of these