1
CBSE 12th Physics (Term 1) Paper 2021-22
+0.77
-0
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 -
A
$${{n{e^2}A} \over {2m\tau l}}$$
B
$${{ml} \over {n{e^2}\tau A}}$$
C
$${{m\tau A} \over {n{e^2}l}}$$
D
$${{n{e^2}\tau A} \over {2ml}}$$
2
CBSE 12th Physics (Term 1) Paper 2021-22
+0.77
-0
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 -
A
$${{{r_1} + {r_2}} \over {{r_2} - {r_1}}}$$
B
$${r_2} - {r_1}$$
C
$${{{r_1}{r_2}} \over {{r_2} - {r_1}}}$$
D
$${{{r_1} + {r_2}} \over {{r_1}{r_2}}}$$
3
CBSE 12th Physics (Term 1) Paper 2021-22
+0.77
-0
The equivalent resistance between A and B of the network shown in figure is

A
3R $$\Omega$$
B
$$\left( {{3 \over 2}} \right)$$R $$\Omega$$
C
2R $$\Omega$$
D
$$\left( {{2 \over 3}} \right)$$R $$\Omega$$
4
CBSE 12th Physics (Term 1) Paper 2021-22
+0.77
-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.
A
Both (A) & (R) are true and (R) is correct explanation of (A).
B
Both (A) & (R) are true and (R) is not correct explanation of (A).
C
(A) is true but (R) is false.
D
(A) is false and (R) is also false.
Class 12 Subjects
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
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Medical
NEET