The core of an efficient transformer should consist of laminated pieces of metal in order to
increase the heat produced by increasing the eddy current
increase the heat produced by reducing the eddy current
reduce the heat produced by increasing the eddy current
reduce the heat produced by reducing the eddy current
Correct answer is D
No explanation has been provided for this answer.
At what frequency would a 10H inductor have a reactance of 2000Ω?
π/200Hz
π/100Hz
100/πHz
100πHz
Correct answer is E
Inductive reactance XL = 2πfL
∴ 2πfL = 2000Ω
then f = 2000Ω/2 x π x 10
f = 100/πHz
motion, the field and the induced current
induced current, the motion and the field
field, the induced current and the motion
induced current, the field and the motion
Correct answer is A
No explanation has been provided for this answer.
2mA
10mA
20mA
25mA
Correct answer is C
Shunt resistance is usually given as
R = igrg/(I - ig)
Where R = 0.05Ω
rg = 5Ω
I = 2M
∴ ig = IR/(rg + R)
= (2 x 0.05)/(5 + 0.05)
= 0.10/5.05
= 0.0198A
= 19.8mA
= 20mA
2A
5A
10A
20A
Correct answer is D
The maximum current drawn by the cooker is given by;
I = \(\frac{P}{V}\)
∴ I = \(\frac{\text{3000}}{200}\)
I = 15A
The fuse rating = I \(\times\) 125% (the fuse is rated at 125% of the normal operating current)
Hence, the fuse rating = 15A \(\times\) (\(\frac{125}{100}\)) = 18.75amps
Therefore, the best fuse is 20A.