A transformer is a power converter that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer’s coils. A varying current in the primary winding creates a varying magnetic flux in the transformer’s core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF), or “voltage”, in the secondary winding. This effect is called inductive coupling. The transformer is based on principle of mutual induction in which, firstly, that an electric current can produce a magnetic field (electromagnetism) and second that a changing magnetic field within a coil of wire induces a voltage across the ends of the coil (electromagnetic induction). Changing the current in the primary coil changes the magnetic flux that is developed. The changing magnetic flux induces a voltage in the secondary coil.

Correct Option: B

A transformer is a power converter that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer’s coils. A varying current in the primary winding creates a varying magnetic flux in the transformer’s core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF), or “voltage”, in the secondary winding. This effect is called inductive coupling. The transformer is based on principle of mutual induction in which, firstly, that an electric current can produce a magnetic field (electromagnetism) and second that a changing magnetic field within a coil of wire induces a voltage across the ends of the coil (electromagnetic induction). Changing the current in the primary coil changes the magnetic flux that is developed. The changing magnetic flux induces a voltage in the secondary coil.

A spoke is one of some number of rods radiating from the center of a wheel (the hub where the axle connects), connecting the hub with the round traction surface. Since bicycle and wheelchair wheel spokes are only in tension, flexible and strong materials such as synthetic fibers, are also occasionally used. Metal spokes used in bicycles also increase the moment of inertia.

Correct Option: A

A spoke is one of some number of rods radiating from the center of a wheel (the hub where the axle connects), connecting the hub with the round traction surface. Since bicycle and wheelchair wheel spokes are only in tension, flexible and strong materials such as synthetic fibers, are also occasionally used. Metal spokes used in bicycles also increase the moment of inertia.

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.

Correct Option: A

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.

If a person throws a ball vertically upwards in a moving train, it comes back to his hand. The moment the ball was thrown, the ball was also in motion alone with the person who had thrown the ball and the train. This is due to inertia of motion. So when the ball remains in the air, both the person and the ball move ahead by the same distance. This makes the ball to come back to his hand on its return.

Correct Option: C

If a person throws a ball vertically upwards in a moving train, it comes back to his hand. The moment the ball was thrown, the ball was also in motion alone with the person who had thrown the ball and the train. This is due to inertia of motion. So when the ball remains in the air, both the person and the ball move ahead by the same distance. This makes the ball to come back to his hand on its return.

The angle of repose or the critical angle of repose, of a granular material is the steepest angle of descent or dip of the slope relative to the horizontal plane when material on the slope face is on the verge of sliding. This angle is in the range 0°–90°.When bulk granular materials are poured onto a horizontal surface, a conical pile will form. The internal angle between the surface of the pile and the horizontal surface is known as the angle of repose and is related to the density, surface area and shapes of the particles, and the coefficient of friction of the material. For certain applications it is more useful to define static friction in terms of the maximum angle before which one of the items will begin sliding. This is called the angle of friction or friction angle. The tangent of the angle of friction is equal to the coefficient of friction. Angle of friction is equal to the angle of repose.

Correct Option: A

The angle of repose or the critical angle of repose, of a granular material is the steepest angle of descent or dip of the slope relative to the horizontal plane when material on the slope face is on the verge of sliding. This angle is in the range 0°–90°.When bulk granular materials are poured onto a horizontal surface, a conical pile will form. The internal angle between the surface of the pile and the horizontal surface is known as the angle of repose and is related to the density, surface area and shapes of the particles, and the coefficient of friction of the material. For certain applications it is more useful to define static friction in terms of the maximum angle before which one of the items will begin sliding. This is called the angle of friction or friction angle. The tangent of the angle of friction is equal to the coefficient of friction. Angle of friction is equal to the angle of repose.