CBSE 12th Physics (Term 1) Paper 2021-22 | Current Electricity Question 15 | Physics

CBSE 12th Physics (Term 1) Paper 2021-22

MCQ (Single Correct Answer)

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If n, e, $$\tau$$ and m have their usual meanings, then the resistance of a wire of length l and cross-sectional area A is given by -

$${{n{e^2}A} \over {2m\tau l}}$$

$${{ml} \over {n{e^2}\tau A}}$$

$${{m\tau A} \over {n{e^2}l}}$$

$${{n{e^2}\tau A} \over {2ml}}$$

CBSE 12th Physics (Term 1) Paper 2021-22

MCQ (Single Correct Answer)

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Two sources of equal emf are connected in series. This combination is, in turn connected to an external resistance R. The internal resistance of two sources are r₁ and r₂ (r₂ > r₁). If the potential difference across the source of internal resistance r₂ is zero, then R equals to -

$${{{r_1} + {r_2}} \over {{r_2} - {r_1}}}$$

$${r_2} - {r_1}$$

$${{{r_1}{r_2}} \over {{r_2} - {r_1}}}$$

$${{{r_1} + {r_2}} \over {{r_1}{r_2}}}$$

CBSE 12th Physics (Term 1) Paper 2021-22

MCQ (Single Correct Answer)

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The equivalent resistance between A and B of the network shown in figure is

CBSE 12th Physics (Term 1) Paper 2021-22 Physics - Current Electricity Question 14 English

CBSE 12th Physics (Term 1) Paper 2021-22 Physics - Current Electricity Question 14 English

3R $$\Omega$$

$$\left( {{3 \over 2}} \right)$$R $$\Omega$$

2R $$\Omega$$

$$\left( {{2 \over 3}} \right)$$R $$\Omega$$

CBSE 12th Physics (Term 1) Paper 2021-22

MCQ (Single Correct Answer)

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-0

Assertion (A) : Higher the range, lower is the resistance of an ammeter.

Reason (R) : To increase the range of an ammeter additional shunt is added in series to it.

Both (A) & (R) are true and (R) is correct explanation of (A).

Both (A) & (R) are true and (R) is not correct explanation of (A).

(A) is true but (R) is false.

(A) is false and (R) is also false.

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