A wire of resistance R is stretched to twice of its original length . Its new resistance will be
  • 2R
  • R/2
  • R/4
  • 4R
The maximum power drawn out of a cell from a source is given by Here E= EMF of cell and r =internal resistance of the cell
  • $\frac {E^2}{r}$
  • $\frac {E^2}{2r}$
  • $\frac {E^2}{3r}$
  • $\frac {E^2}{4r}$
Ohm’s law is not obeyed by
  • electrolytes
  • discharge tube
  • vacuum tubes
  • all of these
Which of the following characteristics of electrons determines the current in a conductor?
  • Thermal velocity alone
  • Drift velocity alone.
  • Both drift velocity and thermal velocity.
  • Neither drift nor thermal velocity
Kirchhoff’s first and second laws of electrical circuits are consequences of
  • conservation of electric charge and energy respectively
  • conservation of energy
  • conservation of electric charge
  • conservation of energy and electric charge respectively
Resistance n, each of r ohm, when connected in parallel give an equivalent resistance of R ohm. if these resistances were connected in series, the combination would have a resistance in ohms, equal to
  • $n^2 R$
  • $nR$
  • $\frac {R}{n}$
  • $\frac {R}{n^2}$
Match the column
current-electricity-class12-mcq-1.png
  • p -> iv, q -> i, r -> ii, s -> iii
  • p -> iv, q -> ii, r -> i, s -> iii
  • p -> iii, q -> iv, r -> ii, s -> i
  • p -> ii, q -> i, r -> iv, s -> iii
The net resistance of the circuit between A and B is
current-electricity-class12-mcq-2.png
  • 8/3 Ω
  • 14/3 Ω
  • 16/3 Ω
  • 22/3 Ω
The charge carriers in a super conductor are
  • protons
  • photons
  • electrons
  • None of the above
A cell supplies a current $I_1$ through a resistor of resistance $R_1$ and a current $l_2$ through a resistor of resistance $R_2$, then internal resistance of the cell is
  • $R_1– R_2$
  • $R_1+ R_2$
  • $\frac {I_1R_2 + I_2R_1}{I_1 + I_2}$
  • $\frac {I_2R_2 - I_1R_1}{I_1 + I_2}$
(a) If both assertion and reason are true and reason is the correct explanation of the assertion. (b) If both assertion and reason are true but reason is not correct explanation of the assertion. (c) If assertion is true, but reason is false. (d) If both assertion and reason are false. (e) If reason is true, but assertion is false Assertion: Ohm's law is applicable for all conducting elements. Reason: Ohm's law is a fundamental law.
  • (a)
  • (b)
  • (c)
  • (d)
  • (e)
(a) If both assertion and reason are true and reason is the correct explanation of the assertion. (b) If both assertion and reason are true but reason is not correct explanation of the assertion. (c) If assertion is true, but reason is false. (d) If both assertion and reason are false. (e) If reason is true, but assertion is false Assertion: The dimensional formula for product of resistance and conductance is same as dielectric constant Reason: Both have the dimension of time constant
  • (a)
  • (b)
  • (c)
  • (d)
  • (e)
(a) If both assertion and reason are true and reason is the correct explanation of the assertion. (b) If both assertion and reason are true but reason is not correct explanation of the assertion. (c) If assertion is true, but reason is false. (d) If both assertion and reason are false. (e) If reason is true, but assertion is false Assertion: Kirchhoff's junction law follows from law of conservation of energy Reason: Kirchhoff's loop law follows from law of conservation of charge
  • (a)
  • (b)
  • (c)
  • (d)
  • (e)
(a) If both assertion and reason are true and reason is the correct explanation of the assertion. (b) If both assertion and reason are true but reason is not correct explanation of the assertion. (c) If assertion is true, but reason is false. (d) If both assertion and reason are false. (e) If reason is true, but assertion is false Assertion: There is no current in the metals in the absence of electric field. Reason: Motion of free electrons are randomly
  • (a)
  • (b)
  • (c)
  • (d)
  • (e)
(a) If both assertion and reason are true and reason is the correct explanation of the assertion. (b) If both assertion and reason are true but reason is not correct explanation of the assertion. (c) If assertion is true, but reason is false. (d) If both assertion and reason are false. (e) If reason is true, but assertion is false Assertion: The e.m.f. of a cell is always greater than the terminal potential difference between its two poles. Reason: There is always some potential drop across the internal resistance of the cell.
  • (a)
  • (b)
  • (c)
  • (d)
  • (e)
In the circuit given below E,F,GH are the cells of emf 2V,1 V,3 V and 1 V and their internal resistance are 2Ω, 1 Ω, 3 Ω and 1 Ω respectively. The value of R is 2 Ω. Find the potential difference  across the resistance R is
current-electricity-class12-mcq-3.png
  • 1/13 V
  • 2/13 V
  • 4/13 V
  • 5/13 V
The current through cell E is
  • 1/13 A
  • 6/13 A
  • 5/13 A
  • 2/13 A
The current through cell H is
  • 1/13 A
  • 2/13 A
  • 5/13 A
  • 6/13 A
Potential difference across the terminals of G is
  • 1.46 V
  • 1.615 V
  • 1.21 V
  • 1.51
Potential difference across the terminals of H is
  • 1.46 V
  • 1.615 V
  • 1.21 V
  • 1.51 V
0 h : 0 m : 1 s

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