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:
32 comments Page 4 of 4.
Fakhur said:
4 years ago
I will assume that this is not in a very hot ambient temperature nor is it sandwiched between other hot components.
In that case, good engineering practice is to use a resistor rated for at least 2x the required power dissipation.
One formula for power is I squared times R.
P = 0.025A^2 x 120 ohms = 0.075W or 75mW.
So, a resistor rated at least double that 150mW.
In that case, good engineering practice is to use a resistor rated for at least 2x the required power dissipation.
One formula for power is I squared times R.
P = 0.025A^2 x 120 ohms = 0.075W or 75mW.
So, a resistor rated at least double that 150mW.
(4)
Pranu said:
1 month ago
energy = power * time.
= v * I * t.
= v * (v/r) * t.
= 15 * (15/12) * (3/60).
= 0.938Wh.
= v * I * t.
= v * (v/r) * t.
= 15 * (15/12) * (3/60).
= 0.938Wh.
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