Eddy Currents

Q. why is the minimum velocity of a a simple pendulum in verticle circular motion at top under root gl

Q. 106. In simple pendulum at lowest point tangential acceleration is zero. Why?

Q. A circular plate of diameter a is kept in contactwith a square plate of side a as shown. Thedensity of the material and the thickness are sameeverywhere. The centre of mass of compositesystem will be3.a→ (1) Inside the circular plate(2) Inside the square plate(3) At the point of contact(4) Outside the systerm

Q. A bar magnet is released into a copper tube. Mass of the magnet is $m$. After some time it gains a constant speed of $v_0$, then heat developed per second in conducting cylinder will be,

1. $mg{v}_0$
2. $\frac{3}{2}mg{v}_0$
3. $\frac{mg{v}_0}{2}$
4. zero

Q. What is eddy current?

Q.

Eddy currents are produced when [CBSE PMT 1993; AFMC 2002]

1. A metal is kept in varying magnetic field

2. A metal is kept in the steady magnetic field

3. A circular coil is placed in a magnetic field

4. Through a circular coil, current is passed