| 4941 |
A material has magnetic susceptibility 499. Its relative permeability is: |
Physics
Bar magnet and magnetic materials |
Medium |
| 4942 |
Magnetic field lines of a bar magnet: |
Physics
Bar magnet and magnetic materials |
Medium |
| 4943 |
When a ferromagnetic substance is heated above its Curie temperature, it becomes: |
Physics
Bar magnet and magnetic materials |
Hard |
| 4944 |
The magnetic flux through a 100-turn coil falls from 0.05 Wb to 0.01 Wb in 0.2 s. The average induced emf is: |
Physics
Faraday’s and Lenz’s laws |
Easy |
| 4945 |
A rod 0.2 m long moves at 10 m/s perpendicular to a uniform field of 0.5 T. The emf across its ends is: |
Physics
Faraday’s and Lenz’s laws |
Easy |
| 4946 |
Lenz’s law is a consequence of the law of conservation of: |
Physics
Faraday’s and Lenz’s laws |
Medium |
| 4947 |
The SI unit of magnetic flux is: |
Physics
Faraday’s and Lenz’s laws |
Medium |
| 4948 |
The cores of transformers are laminated mainly to: |
Physics
Faraday’s and Lenz’s laws |
Hard |
| 4949 |
The current in a 0.2 H coil falls uniformly from 5 A to zero in 0.1 s. The average self-induced emf is: |
Physics
Self and mutual induction |
Easy |
| 4950 |
The energy stored in an inductor of 0.2 H carrying 5 A is: |
Physics
Self and mutual induction |
Easy |
| 4951 |
The SI unit of inductance is: |
Physics
Self and mutual induction |
Medium |
| 4952 |
If the number of turns of a solenoid is doubled, keeping its length and area the same, its self-inductance be… |
Physics
Self and mutual induction |
Medium |
| 4953 |
The mutual inductance between two coils does NOT depend on: |
Physics
Self and mutual induction |
Hard |
| 4954 |
The peak value of an AC voltage is 325 V. Its RMS value is about: |
Physics
Alternating current |
Easy |
| 4955 |
The reactance of a 0.1 H inductor at 50 Hz is about: |
Physics
Alternating current |
Easy |
| 4956 |
A series LCR circuit has R = 30 Ω, X_L = 80 Ω and X_C = 40 Ω. Its impedance is: |
Physics
Alternating current |
Medium |
| 4957 |
In a purely inductive AC circuit, the current: |
Physics
Alternating current |
Medium |
| 4958 |
As the frequency of the AC supply increases, the reactance of a capacitor: |
Physics
Alternating current |
Hard |
| 4959 |
A series LCR circuit has L = 0.1 H and C = 10 μF. Its resonant frequency is about: |
Physics
Resonance and power in AC circuits |
Medium |
| 4960 |
At resonance in a series LCR circuit, the impedance is: |
Physics
Resonance and power in AC circuits |
Easy |