Question 1.21: A current of 20 mA flows in a 1 kΩ resistor. What power is d...
A current of 20 mA flows in a 1 kΩ resistor. What power is dissipated in the resistor?
Here we use P = I^2 × R but, to make life a little easier, we will work in mA and kΩ (in which case the answer will be in mW).
P = I^2 × R = (20 mA × 20 mA) × 1 kΩ = 400 mW
Thus a power of 400 mW is dissipated in the 1 kΩ resistor.
Related Answered Questions
Question: 1.16
Verified Answer:
R = V / I = 15 V / 0.001 A = 15,000 Ω = 15...
Question: 1.15
Verified Answer:
Here we must use V = I × R and en...
Question: 1.26
Verified Answer:
Now B = Φ /A = (0.8 × 10^{−3}) / (500 × 10...
Question: 1.25
Verified Answer:
From Fig. 1.18, the slope of the graph at any poin...
Question: 1.24
Verified Answer:
Re-arranging the formula B=\Phi /A [/latex...
Question: 1.23
Verified Answer:
Applying the formula B=\mu _0 \ I /2\pi \ ...
Question: 1.22
Verified Answer:
The electric field strength will be given by:
[lat...
Question: 1.20
Verified Answer:
Here we use P = V ^2 / R (\text { where } ...
Question: 1.19
Verified Answer:
Here we must use P = I × V (where...
Question: 1.18
Verified Answer:
First we must find the resistance of the wire (as ...