1
WB JEE 2022
MCQ (Single Correct Answer)
+1
-0.25
Change Language

A straight wire is placed in a magnetic field that varies with distance x from origin as $$\overrightarrow B = {B_0}\left( {2 - {x \over a}} \right)\widehat k$$. Ends of wire are at (a, 0) and (2a, 0) and it carries a current I. If force on wire is $$\overrightarrow F = I{B_0}\left( {{{ka} \over 2}} \right)\widehat j$$, then value of k is

A
1
B
5
C
$$-$$1
D
$${1 \over 2}$$
2
WB JEE 2022
MCQ (Single Correct Answer)
+1
-0.25
Change Language

In a closed circuit there is only a coil of inductance L and resistance 100 $$\Omega$$. The coil is situated in a uniform magnetic field. All on a sudden, the magnetic flux linked with the circuit changes by 5 Weber. What amount of charge will flow in the circuit as a result?

A
500 C
B
0.05 C
C
20 C
D
Value of L is to be known to find the charge flown
3
WB JEE 2022
MCQ (Single Correct Answer)
+1
-0.25
Change Language

When an AC source of emf E with frequency $$\omega$$ = 100 Hz is connected across a circuit, the phase difference between E and current I in the circuit is observed to be $${\pi \over 4}$$ as shown in the figure. If the circuit consist of only RC or RL in series, then

WB JEE 2022 Physics - Alternating Current Question 1 English

A
R = 1 k$$\Omega$$, C = 5 $$\mu$$F
B
R = 1 k$$\Omega$$, L = 10 H
C
R = 1 k$$\Omega$$, L = 1 H
D
R = 1 k$$\Omega$$, C = 10 $$\mu$$F
4
WB JEE 2022
MCQ (Single Correct Answer)
+1
-0.25
Change Language

WB JEE 2022 Physics - Current Electricity Question 12 English

A battery of emf E and internal resistance r is connected with an external resistance R as shown in the figure. The battery will act as a constant voltage source if

A
r << R
B
r >> R
C
r = R
D
It will never act as a constant voltage source.
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