A conducting wire carrying current is arranged as shown in the figure. The magnetic field at O is
A.
The magnetic field at the centre due to an arc carrying-current is given by the formula,
Here, θ = 60° =
The magnetic field due to R1 radius part.
The quantity of a charge that will be transferred by a current flow of 20 A over 1 h 30 min period is
10.8 × 103 C
10.8 × 104 C
5.4 × 103 C
1.8 × 104 C
A galvanometer coil has a resistance of 50 Ω and the meter shows full scale deflection for a current of 5 mA. This galvanometer is converted into voltmeter of range 0-20 V by connecting
3950 Ω in series with galvanometer
4050 Ω in series with galvanometer
3950 Ω in parallel with galvanometer
4050 Ω in parallel with galvanometer
and are susceptibility of a paramagnetic material at temperatures T1 K and T2 K respectively, then
At certain place, the horizontal component of Earth's magnetic field is 3.0 G and the angle dip at that place is 30°. The magnetic field of Earth at that location is
4.5 G
5.1 G
3.5 G
6.0 G
A long solenoid with 40 turns per cm carries a current of 1 A. The magnetic energy stored per unit volume is
A wheel with 10 spokes each of length L m is rotated with a uniform angular velocity ω in a plane normal to the magnetic field B. The emf induced between the axle and the rim of the wheel is
NωBL2
The rms value of current in a 50 Hz AC circuit is 6 A. The average value of AC current over a cycle is
Zero
A capacitor of capacitance 10 µF is connected to an AC ammeter. If the source voltage varies as , the reading of the ammeter is
50 mA
70.7 mA
5.0 mA
7.07 mA
In a series L-C-R circuit, the potential drop across L, C and R respectively are 40 V, 120 V and 60 V. Then, the source voltage is
220 V
160 V
180 V
100 V