Advertisements
Advertisements
Question
The V-I graph for a series combination and for a parallel combination of two resistors is shown in Fig – 8.38. Which of the two, A or B, represents the parallel combination? Give a reason for your answer.
Advertisements
Solution
For the same change in I, change in V is less for the straight line A than for the straight line B (i.e., the straight line A is less steeper than B), so the straight line A represents small resistance, while the straight line B represents more resistance. In parallel combination, the resistance decreases while in series combination, the resistance increases. So A represents the parallel combination.
RELATED QUESTIONS
State two causes of energy loss in a transformer.
State the relation between potential difference, work done and charge moved.
A p.d. of 10 V is needed to make a current of 0.02 A flow through a wire. Wire p.d. is needed to make a current of 250 mA flow through the same wire?
How does the resistance of a metallic wire depend on its temperature? Explain with reason.
Electric cells having 2V potential difference each have been connected in the form of a battery. What will be the total potential difference of the battery in both cases?
Write an expression for the electrical power spent in flow of current through a conductor in terms of resistance and potential difference.
Point out two differences between e.m.f. and potential difference as applied to electric circuits.
In the figure given below, A, B and C are three ammeters. The ammeter B reads 0.5A. (All the ammeters have negligible resistance.)
Calculate:
(i) the readings in the ammeters A and C.
(ii) the total resistance of the circuit.
A cell of e.m.f 2.0 V and internal resistance 1Ω is connected to the resistors of 3Ω and 6Ω in series. Calculate:
(i) the current drawn from the cell,
(ii) the p.d. across each resistor,
(iii) the terminal voltage of the cell and
(iv) the voltage drop.
How will you conclude that the same potential difference (voltage) exists across three resistors connected in a parallel arrangement to a battery?
