QBManager

PHXII07:ALTERNATING CURRENT

356031 The figure shows three circuits with identical batteries, inductors and resistance. Rank the circuits according to the currents through the battery just after the switch is closed, greatest first.
supporting img

1

i_{2} > i_{3} > i_{1}

2

i_{2} > i_{1} > i_{3}

3

i_{1} > i_{2} > i_{3}

4

i_{1} > i_{3} > i_{2}

Explanation:

In circuit (1), on closing the switch, the current in the inductor is zero due to selfinduction, $i . e .$ $i_{1} = 0$ .
In circuit (2), on closing the switch, the current in the inductor is zero dut to self-induction.
supporting img
Therefore, $i_{2} = i = \frac{E}{R_{1}}$
In circuit (3), on closing the switch, the current in the inductor is again zero due to the same reason.

Therefore, $i_{3} = i = \frac{E}{R_{1} + R_{2}}$
Thus, it is obvious that, $i_{2} > i_{3} > i_{1} (= 0)$ .

AIIMS - 2007

PHXII07:ALTERNATING CURRENT

356032 A coil has resistance $30 o h m$ and inductive reactance $20 o h m$ at $50 H z$ frequency. If an ac source, of $200 v o l t$ , $100 H z$ , is connected across the coil, the current in the coil will be

1

4.0 A

2

8.0 A

3

7.2 A

4

2.0 A

Explanation:

If $ω = 50 \times 2 π$ then $ω L = 20 Ω$
If $ω^{'} = 100 \times 2 π$ then $ω^{'} L = 40 Ω$
Current flowing in the coil is
$I = \frac{200}{Z} = \frac{200}{\sqrt{R^{2} + {(ω^{'} L)}^{2}}} = 4 A$

PHXII07:ALTERNATING CURRENT

356033 Assertion :
Average value of ac over a complete cycle is always zero.
Reason :
A choke coil consists of an inductor having some resistance R.

1 Both assertion and reason are correct and reason is the correct explanation of assertion.

2 Both assertion and reason are correct but reason is not the correct explanation of assertion.

3 Assertion is correct but reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXII07:ALTERNATING CURRENT

356034 An inducer and a resistor in series are connected to an $A . C$ supply of variable frequency. As the frequency of the source is increased, the phase angle between current and the potential difference across the circuit will:
supporting img

1 first increase and then decrease

2 first decrease and then increase

3 go on decreasing

4 go on increasing

Explanation:

$\tan θ = \frac{X_{L}}{R} = \frac{2 π v L}{R}$
As $v$ increases $θ$ also increases.

PHXII07:ALTERNATING CURRENT

356035 The graph given below depict the dependence of two reactive impedances $X_{1}$ and $X_{2}$ on the frequency of the alternating e.m.f. applied individually to them. We can then say that
supporting img

1

X_{1}

is an inductor and

X_{2}

is a capacitor

2

X_{1}

is a resistor and

X_{2}

is a capacitor

3

X_{1}

is a capacitor and

X_{2}

is an inductor

4

X_{1}

is an inductor and

X_{2}

is a resistor

PHXII07:ALTERNATING CURRENT

356031 The figure shows three circuits with identical batteries, inductors and resistance. Rank the circuits according to the currents through the battery just after the switch is closed, greatest first.
supporting img

1

i_{2} > i_{3} > i_{1}

2

i_{2} > i_{1} > i_{3}

3

i_{1} > i_{2} > i_{3}

4

i_{1} > i_{3} > i_{2}

Explanation:

In circuit (1), on closing the switch, the current in the inductor is zero due to selfinduction, $i . e .$ $i_{1} = 0$ .
In circuit (2), on closing the switch, the current in the inductor is zero dut to self-induction.
supporting img
Therefore, $i_{2} = i = \frac{E}{R_{1}}$
In circuit (3), on closing the switch, the current in the inductor is again zero due to the same reason.

Therefore, $i_{3} = i = \frac{E}{R_{1} + R_{2}}$
Thus, it is obvious that, $i_{2} > i_{3} > i_{1} (= 0)$ .

AIIMS - 2007

PHXII07:ALTERNATING CURRENT

356032 A coil has resistance $30 o h m$ and inductive reactance $20 o h m$ at $50 H z$ frequency. If an ac source, of $200 v o l t$ , $100 H z$ , is connected across the coil, the current in the coil will be

1

4.0 A

2

8.0 A

3

7.2 A

4

2.0 A

Explanation:

If $ω = 50 \times 2 π$ then $ω L = 20 Ω$
If $ω^{'} = 100 \times 2 π$ then $ω^{'} L = 40 Ω$
Current flowing in the coil is
$I = \frac{200}{Z} = \frac{200}{\sqrt{R^{2} + {(ω^{'} L)}^{2}}} = 4 A$

PHXII07:ALTERNATING CURRENT

356033 Assertion :
Average value of ac over a complete cycle is always zero.
Reason :
A choke coil consists of an inductor having some resistance R.

1 Both assertion and reason are correct and reason is the correct explanation of assertion.

2 Both assertion and reason are correct but reason is not the correct explanation of assertion.

3 Assertion is correct but reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXII07:ALTERNATING CURRENT

356034 An inducer and a resistor in series are connected to an $A . C$ supply of variable frequency. As the frequency of the source is increased, the phase angle between current and the potential difference across the circuit will:
supporting img

1 first increase and then decrease

2 first decrease and then increase

3 go on decreasing

4 go on increasing

Explanation:

$\tan θ = \frac{X_{L}}{R} = \frac{2 π v L}{R}$
As $v$ increases $θ$ also increases.

PHXII07:ALTERNATING CURRENT

356035 The graph given below depict the dependence of two reactive impedances $X_{1}$ and $X_{2}$ on the frequency of the alternating e.m.f. applied individually to them. We can then say that
supporting img

1

X_{1}

is an inductor and

X_{2}

is a capacitor

2

X_{1}

is a resistor and

X_{2}

is a capacitor

3

X_{1}

is a capacitor and

X_{2}

is an inductor

4

X_{1}

is an inductor and

X_{2}

is a resistor

PHXII07:ALTERNATING CURRENT

356031 The figure shows three circuits with identical batteries, inductors and resistance. Rank the circuits according to the currents through the battery just after the switch is closed, greatest first.
supporting img

1

i_{2} > i_{3} > i_{1}

2

i_{2} > i_{1} > i_{3}

3

i_{1} > i_{2} > i_{3}

4

i_{1} > i_{3} > i_{2}

Explanation:

In circuit (1), on closing the switch, the current in the inductor is zero due to selfinduction, $i . e .$ $i_{1} = 0$ .
In circuit (2), on closing the switch, the current in the inductor is zero dut to self-induction.
supporting img
Therefore, $i_{2} = i = \frac{E}{R_{1}}$
In circuit (3), on closing the switch, the current in the inductor is again zero due to the same reason.

Therefore, $i_{3} = i = \frac{E}{R_{1} + R_{2}}$
Thus, it is obvious that, $i_{2} > i_{3} > i_{1} (= 0)$ .

AIIMS - 2007

PHXII07:ALTERNATING CURRENT

356032 A coil has resistance $30 o h m$ and inductive reactance $20 o h m$ at $50 H z$ frequency. If an ac source, of $200 v o l t$ , $100 H z$ , is connected across the coil, the current in the coil will be

1

4.0 A

2

8.0 A

3

7.2 A

4

2.0 A

Explanation:

If $ω = 50 \times 2 π$ then $ω L = 20 Ω$
If $ω^{'} = 100 \times 2 π$ then $ω^{'} L = 40 Ω$
Current flowing in the coil is
$I = \frac{200}{Z} = \frac{200}{\sqrt{R^{2} + {(ω^{'} L)}^{2}}} = 4 A$

PHXII07:ALTERNATING CURRENT

356033 Assertion :
Average value of ac over a complete cycle is always zero.
Reason :
A choke coil consists of an inductor having some resistance R.

1 Both assertion and reason are correct and reason is the correct explanation of assertion.

2 Both assertion and reason are correct but reason is not the correct explanation of assertion.

3 Assertion is correct but reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXII07:ALTERNATING CURRENT

356034 An inducer and a resistor in series are connected to an $A . C$ supply of variable frequency. As the frequency of the source is increased, the phase angle between current and the potential difference across the circuit will:
supporting img

1 first increase and then decrease

2 first decrease and then increase

3 go on decreasing

4 go on increasing

Explanation:

$\tan θ = \frac{X_{L}}{R} = \frac{2 π v L}{R}$
As $v$ increases $θ$ also increases.

PHXII07:ALTERNATING CURRENT

356035 The graph given below depict the dependence of two reactive impedances $X_{1}$ and $X_{2}$ on the frequency of the alternating e.m.f. applied individually to them. We can then say that
supporting img

1

X_{1}

is an inductor and

X_{2}

is a capacitor

2

X_{1}

is a resistor and

X_{2}

is a capacitor

3

X_{1}

is a capacitor and

X_{2}

is an inductor

4

X_{1}

is an inductor and

X_{2}

is a resistor

PHXII07:ALTERNATING CURRENT

356031 The figure shows three circuits with identical batteries, inductors and resistance. Rank the circuits according to the currents through the battery just after the switch is closed, greatest first.
supporting img

1

i_{2} > i_{3} > i_{1}

2

i_{2} > i_{1} > i_{3}

3

i_{1} > i_{2} > i_{3}

4

i_{1} > i_{3} > i_{2}

Explanation:

In circuit (1), on closing the switch, the current in the inductor is zero due to selfinduction, $i . e .$ $i_{1} = 0$ .
In circuit (2), on closing the switch, the current in the inductor is zero dut to self-induction.
supporting img
Therefore, $i_{2} = i = \frac{E}{R_{1}}$
In circuit (3), on closing the switch, the current in the inductor is again zero due to the same reason.

Therefore, $i_{3} = i = \frac{E}{R_{1} + R_{2}}$
Thus, it is obvious that, $i_{2} > i_{3} > i_{1} (= 0)$ .

AIIMS - 2007

PHXII07:ALTERNATING CURRENT

356032 A coil has resistance $30 o h m$ and inductive reactance $20 o h m$ at $50 H z$ frequency. If an ac source, of $200 v o l t$ , $100 H z$ , is connected across the coil, the current in the coil will be

1

4.0 A

2

8.0 A

3

7.2 A

4

2.0 A

Explanation:

If $ω = 50 \times 2 π$ then $ω L = 20 Ω$
If $ω^{'} = 100 \times 2 π$ then $ω^{'} L = 40 Ω$
Current flowing in the coil is
$I = \frac{200}{Z} = \frac{200}{\sqrt{R^{2} + {(ω^{'} L)}^{2}}} = 4 A$

PHXII07:ALTERNATING CURRENT

356033 Assertion :
Average value of ac over a complete cycle is always zero.
Reason :
A choke coil consists of an inductor having some resistance R.

1 Both assertion and reason are correct and reason is the correct explanation of assertion.

2 Both assertion and reason are correct but reason is not the correct explanation of assertion.

3 Assertion is correct but reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXII07:ALTERNATING CURRENT

356034 An inducer and a resistor in series are connected to an $A . C$ supply of variable frequency. As the frequency of the source is increased, the phase angle between current and the potential difference across the circuit will:
supporting img

1 first increase and then decrease

2 first decrease and then increase

3 go on decreasing

4 go on increasing

Explanation:

$\tan θ = \frac{X_{L}}{R} = \frac{2 π v L}{R}$
As $v$ increases $θ$ also increases.

PHXII07:ALTERNATING CURRENT

356035 The graph given below depict the dependence of two reactive impedances $X_{1}$ and $X_{2}$ on the frequency of the alternating e.m.f. applied individually to them. We can then say that
supporting img

1

X_{1}

is an inductor and

X_{2}

is a capacitor

2

X_{1}

is a resistor and

X_{2}

is a capacitor

3

X_{1}

is a capacitor and

X_{2}

is an inductor

4

X_{1}

is an inductor and

X_{2}

is a resistor

PHXII07:ALTERNATING CURRENT

356031 The figure shows three circuits with identical batteries, inductors and resistance. Rank the circuits according to the currents through the battery just after the switch is closed, greatest first.
supporting img

1

i_{2} > i_{3} > i_{1}

2

i_{2} > i_{1} > i_{3}

3

i_{1} > i_{2} > i_{3}

4

i_{1} > i_{3} > i_{2}

Explanation:

In circuit (1), on closing the switch, the current in the inductor is zero due to selfinduction, $i . e .$ $i_{1} = 0$ .
In circuit (2), on closing the switch, the current in the inductor is zero dut to self-induction.
supporting img
Therefore, $i_{2} = i = \frac{E}{R_{1}}$
In circuit (3), on closing the switch, the current in the inductor is again zero due to the same reason.

Therefore, $i_{3} = i = \frac{E}{R_{1} + R_{2}}$
Thus, it is obvious that, $i_{2} > i_{3} > i_{1} (= 0)$ .

AIIMS - 2007

PHXII07:ALTERNATING CURRENT

356032 A coil has resistance $30 o h m$ and inductive reactance $20 o h m$ at $50 H z$ frequency. If an ac source, of $200 v o l t$ , $100 H z$ , is connected across the coil, the current in the coil will be

1

4.0 A

2

8.0 A

3

7.2 A

4

2.0 A

Explanation:

If $ω = 50 \times 2 π$ then $ω L = 20 Ω$
If $ω^{'} = 100 \times 2 π$ then $ω^{'} L = 40 Ω$
Current flowing in the coil is
$I = \frac{200}{Z} = \frac{200}{\sqrt{R^{2} + {(ω^{'} L)}^{2}}} = 4 A$

PHXII07:ALTERNATING CURRENT

356033 Assertion :
Average value of ac over a complete cycle is always zero.
Reason :
A choke coil consists of an inductor having some resistance R.

1 Both assertion and reason are correct and reason is the correct explanation of assertion.

2 Both assertion and reason are correct but reason is not the correct explanation of assertion.

3 Assertion is correct but reason is incorrect.

4 Assertion is incorrect but reason is correct.

PHXII07:ALTERNATING CURRENT

356034 An inducer and a resistor in series are connected to an $A . C$ supply of variable frequency. As the frequency of the source is increased, the phase angle between current and the potential difference across the circuit will:
supporting img

1 first increase and then decrease

2 first decrease and then increase

3 go on decreasing

4 go on increasing

Explanation:

$\tan θ = \frac{X_{L}}{R} = \frac{2 π v L}{R}$
As $v$ increases $θ$ also increases.

PHXII07:ALTERNATING CURRENT

356035 The graph given below depict the dependence of two reactive impedances $X_{1}$ and $X_{2}$ on the frequency of the alternating e.m.f. applied individually to them. We can then say that
supporting img

1

X_{1}

is an inductor and

X_{2}

is a capacitor

2

X_{1}

is a resistor and

X_{2}

is a capacitor

3

X_{1}

is a capacitor and

X_{2}

is an inductor

4

X_{1}

is an inductor and

X_{2}

is a resistor