Advertisements
Advertisements
Question
A current of 0.2 A flows through a wire whose ends are at a potential difference of 15 V. Calculate:
(i) The resistance of the wire, and
(ii) The heat energy produced in 1 minute.
Advertisements
Solution
Given ,
Current, I = 0.2 A
Potential difference , V = 15 V
Time ,t = 60 sec
As V = IR
(a) R = `15/0.2 = 75 Omega`
(b) Heat energy , H = I2Rt
H = (0.2)2 × 75 × 60
or H = 180 J
RELATED QUESTIONS
Fill in the blank:
To increase the effective resistance in a circuit the resistors are connected in _____________.
A flash of lighting carries 10 C of charge which flows for 0.01 s. What is the current? If the voltage is 10 MV, what is the energy?
If the current through a floodlamp is 5 A, what charge passed in 10 seconds?
(a) 0.5 C
(b) 2 C
(c) 5 C
(d) 50 C
Using the circuit given below, state which of the following statement is correct?
(a) When S1 and S2 are closed, lamps A and B are lit.22
(b) With S1 open and S2 closed, A is lit and B is not lit.
(c) With S2 open and S1 closed A and B are lit.
(d) With S1 closed and S2 open, lamp A remains lit even if lamp B gets fused.
Consider the circuit given below when A, B and C are three identical light bulbs of constant resistance. 
(a) List the bulbs in order of increasing brightness.
(b) If C burns out, what will be the brightness of A now compared with before?
(c) If B burns out instead, what will be the brightness of A and C compared with before?
Conventionally, the direction of the current is taken as:
Calculate the current in a wire if a charge of 1500 coulomb flows through it in 5 minutes.
Find the odd one out.
Loudspeaker, Bar magnet/magnet, Electric motor, Microphone.
