Electrical Engineering - Energy and Power - Discussion
Discussion Forum : Energy and Power - General Questions (Q.No. 7)
7.
A 15 V source is connected across a 12 
resistor. How much energy is used in three minutes?
resistor. How much energy is used in three minutes?Discussion:
31 comments Page 2 of 4.
Satish mahadu kukade said:
8 years ago
You are correct @Debu.
Zahid said:
9 years ago
Well said @Bains and @Debu.
RAVI said:
1 decade ago
15/12 = 1.25 A.
3/60 = 0.05 H.
P = 15*1.25 = 18.75 W.
E = 18.75*0.05 = 0.9375 WH.
3/60 = 0.05 H.
P = 15*1.25 = 18.75 W.
E = 18.75*0.05 = 0.9375 WH.
Pankaj R.Patil said:
1 decade ago
v^2/r*t, t in hours.
Naser said:
1 decade ago
15*15/12 = 18.75.
18.75/60 = 0.3125.
0.3125*3 = 0.9375 wh.
18.75/60 = 0.3125.
0.3125*3 = 0.9375 wh.
Hazrat Bilal Safi said:
1 decade ago
@Aramuthan. You are wrong.
P = IV;
I = V/R;
Since,
I = 15/12.
I = 1.25A.
P = 1.25*15 = 18.75.
3 minute= 3/60 hours = 0.05h.
Energy= 18.75* 0.05= 0.9375Wh.
P = IV;
I = V/R;
Since,
I = 15/12.
I = 1.25A.
P = 1.25*15 = 18.75.
3 minute= 3/60 hours = 0.05h.
Energy= 18.75* 0.05= 0.9375Wh.
Mohamed Basha j said:
1 decade ago
P = V^2 / R , so P= 15^2*12 p = 18.75watts.
For 3 min = 3/60 = .05.
Used Energy = 18.75 * .05.
= 0.9375 Wh.
Answer = option B.
For 3 min = 3/60 = .05.
Used Energy = 18.75 * .05.
= 0.9375 Wh.
Answer = option B.
Ravi26v said:
1 decade ago
((V*V)/ R)*time in hrs
Mrakovic said:
1 decade ago
W = U^2/R.
W = 225/12 = 18.75W.
3 min = 0.05h.
Wh = W*t = 18.75*0.05 = 0.9375Wh.
W = 225/12 = 18.75W.
3 min = 0.05h.
Wh = W*t = 18.75*0.05 = 0.9375Wh.
Anonymous said:
1 decade ago
Why can't we use the formula V^2/R*t?
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