12. Calculate the potential difference required across a conductor of resistance 57
to make a current of 1.5A flow through it.
13. What is the resistance of an electric are lamp when hot, if the lamp uses 20A
when connected to a 220V line?
14. Calculate the amount of work done to draw a current of 8A from a point at
100V to a point at 120V in 2 seconds.
15. If 200C of charge pass a point in a circuit in 4 sec, what current is flowing?
16. A current of 4A flows around a circuit in 10 seconds. How much charge flows
past a point in the circuit in this time? Also find the number of electrons passes
in the circuit
Answers
12} R = 5 Ω and I = 1.5 A Potential difference V = IR = 1.5 A x 5 Ω = 7.5 V.
13} I = 20 A
V = 220 V
R=V/I
=220/20
= 11 ohms
14} I=Q/T
8A = Q/2S
Q = 16C
FOR CALCULATING WORK DONE
V=W/Q
100=W/16
W=1600
120=W/Q
W=1920
HENCE WORK DONE IS 320(1920-1600)
Q.2 I=Q/T
0.4 = Q/10800
(t=3×3600=10800)
Q =10800×0.4=4320
so the charge is 4320 coulomb
15} 20 Amps
16} at pic attached
Mark as brainliest
12. R=57ohm
I=1.5A
According to ohm's law
V=IR
V=1.5*57
V=85.5V
13. I=20A
V=220V
According to ohm's law
V=IR
R=V/I
R=220/20
R=11ohm
14. V1=100V
V2=120V
V=V2-V1
V=120-100=20V
I=8A
T=2sec
I=Q/T
Q=I*T
Q=8*2
Q=16C
V=W/Q
W=V*Q
W=20*16
W=320J
15.Q=200C
T=4sec
I=Q/T
I=200/4
I=50A
16.I=4A
T=10sec
I=Q/T
Q=I*T
Q=4*10
Q=40C
Q=ne (where n is no. of electrons and e is charge of electrons)
40=n*1.6×10^-19
n=40/1.6×10^-19
n=25×10^19