Physics - Study Mode
[#306] Intensity of gravitational field of earth is maximum at
Correct Answer
(A) Poles
Explanation
Solution: A perfect sphere of spherically uniform density (density varies solely with distance from centre) would produce a gravitational field of uniform magnitude at all points on its surface, always pointing directly towards the sphere’s centre. However, the Earth deviates slightly from this ideal, and there are consequently slight deviations in both the magnitude and direction of gravity across its surface. Furthermore, the net force exerted on an object due to the Earth, called “effective gravity” or “apparent gravity”, varies due to the presence of other factors, such as inertial response to the Earth’s rotation. A scale or plumb bob measures only this effective gravity. The major reason for the difference in gravity at different latitudes is that the Earth’s equatorial bulge (itself also caused by inertia) causes objects at the Equator to be farther from the planet’s centre than objects at the poles. Because the force due to gravitational attraction between two bodies (the Earth and the object being weighed) varies inversely with the square of the distance between them, an object at the Equator experiences a weaker gravitational pull than an object at the poles.
[#307] By how many times are the Electrostatic forces stronger than the Gravitational Forces for a fixed distance?
Correct Answer
(B) 10 36
Explanation
Solution: Electrostatic forces are 10 36 times stronger than the Gravitational Forces for a fixed distance.
[#308] Which is the point from where an azimuth originates?
Correct Answer
(B) North
Explanation
Solution: The azimuth originates at true North i.e, the azimuth originates from the north point. It is a measure of how far an object forms the observer's north point.
[#309] The weight of a body acts through the centre of
Correct Answer
(A) Gravity
Explanation
Solution: The centre of gravity of a collection of masses is the point where all the weight of the object can be considered to be concentrated. The entire weight acts through the center of gravity instead of acting through the individual masses. In a uniform gravitational field (like the field close to the surface of the Earth) the Centres of Gravity and Mass are in exactly the same place.
[#310] If the spinning speed of the earth is increased then the weight of body at the equator
Correct Answer
(B) Decreases
Explanation
Solution: If the spinning speed of the earth is increased then the weight of body at the equator decreases.