Physics Test 130

In an ideal parallel L-C circuit, the capacitor is charged by connecting it to a DC source which is then disconnected. The current in the circuit

The rms value of AC voltage is  v 3+4 sin (100 πt )

Two coils C1 & C2 are placed adjacent to each other, if current is changed in coil C1 at a rate of 5A/sec, the emf induced in coil C2 is 20mV. What emf will be induced in 7C1 if the current is changed in Coil C2 at a rate of 7 A/Sec (Assume there is no change in orientation or position of the coils) 

A magnetic needle is kept in a non uniform magnetic field. It experiences 

A Cu ring is suspended by a thread in a vertical plane. The north pole of a magnet is brought near the ring in horizontal direction as shown in figure. What will be effect on the ring ? 

An emf  E = 4 Cos 1000 t volt is applied to an L-R circuit of inductance 3 mH and resistance 4 Ω. The amplitude of the current in the circuit is

Assertion : A.C. is more dangerous than D.C.

Reason: The peak value of A.C. is 41.4% higher than the D.C

Assertion: Self Inductance is also known as inertia of electricity.

Reason : Self Inductance is the property of Coil due to which the coil opposes the flow current through it

Assertion: In the phenomenon of mutual induction self induction of each of the coils persists

Reason: Self induction arises when strength of current in one coil changes. In this case, current may be changing in both the individual coils

Assertion: When number of turns in a coil is doubled, coefficient of self-inductance of the coil becomes 4 times

Reason : This is because L ∞ N²