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.
Tejswee said:
1 decade ago
Energy = Power*Time = (i^2*r)*(3/60) = 0.9375
(1)
Pratap sahu said:
1 decade ago
Let
V = 15, R = 12.
So I = V/R = 15/12 = 1.25 A.
And P=V*I, So P = 15*1.25 = 18.75wh.
In 1 hour power will consume 18.75wh.
In 1 minute power will consume = 18.75/60 = 0.3125wh.
In 3 minute power will consume = 0.3125*3 = 0.9375wh.
V = 15, R = 12.
So I = V/R = 15/12 = 1.25 A.
And P=V*I, So P = 15*1.25 = 18.75wh.
In 1 hour power will consume 18.75wh.
In 1 minute power will consume = 18.75/60 = 0.3125wh.
In 3 minute power will consume = 0.3125*3 = 0.9375wh.
Naresh Jadav said:
1 decade ago
Let,
3 minite = 0.05h.
I = V/R.
=15/12 = 1.25 A.
Power = V*I = 12*1.25 = 18.75w.
Now,
W*h = 18.75*0.05 = 0.9375wh.
3 minite = 0.05h.
I = V/R.
=15/12 = 1.25 A.
Power = V*I = 12*1.25 = 18.75w.
Now,
W*h = 18.75*0.05 = 0.9375wh.
Anonymous said:
1 decade ago
Why can't we use the formula V^2/R*t?
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.
BIPRADAS GHOSH said:
1 decade ago
Energy = (I)2Rt.
I = V/R = 15/12 = 1.25.
R = 12 and t = 3 min = 3/60 hr = 0.05 hr.
So, Energy = (1.25)2*12*0.05 = 0.9375.
I = V/R = 15/12 = 1.25.
R = 12 and t = 3 min = 3/60 hr = 0.05 hr.
So, Energy = (1.25)2*12*0.05 = 0.9375.
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.
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.
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.
Pankaj R.Patil said:
1 decade ago
v^2/r*t, t in hours.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers