Physics Practice: Electromagnetism (Mock Test 3 - Advanced)
1. Advanced Analysis: If a DC motor is used as a generator by rotating its armature manually, what kind of current will it produce at the brushes?
2. Flux Logic: A circular loop of area $A$ is placed in a uniform magnetic field $B$. The magnetic flux linked with the loop is maximum when the plane of the loop is:
3. Why is the efficiency of a practical transformer always less than $100\%$?
4. Lenz's Law indicates that the induced current always ________ the change in magnetic flux that produced it.
5. Which of the following setup will NOT induce an e.m.f. in a coil?
6. In a step-up transformer, if the input power is $100 \text{ W}$, the output power (assuming $10 \%$ loss) will be:
7. A split-ring commutator in a DC motor is used to:
8. What happens to the magnetic field of a solenoid if the direction of current is reversed?
9. The phenomenon of "Self-Induction" is often called the ________ of electricity.
10. For an ideal transformer, the relation between current ($I$) and voltage ($V$) is:
