Calculate the energy stored in a 20\(\mu F\) capacitor. If the p.d between the plates is 40V
3.2 x 10-2J
1.6 x 10-2J
8.0 x 10-4J
4.0 x 10-4J
Correct answer is B
W = \(\frac{cv^2}{2} = \frac{20 \times 10^{-6} \times 40^{2}}{2}\)
= 1.6 x 10-2J
The quantity of electric charge stored in a capacitor is measured in
farad
ampere
coulomb
volt
Correct answer is C
No explanation has been provided for this answer.
Find the cost of running a 60W lamp for 24 hours. If 1kW hr cost 5 naira
14.4 naira
12.5 naira
7.2 naira
2.0 naira
Correct answer is C
Cost = P(Kwh) x Cost per KW
= \(\frac{60 \times 24}{1000} \times N5 = N7.2\)
A car fuse marked 3A operates optimally on a 12V battery, calculate the resistance of the fuse
36.0\(\Omega\)
15.0\(\Omega\)
9.0\(\Omega\)
4.0\(\Omega\)
Correct answer is D
R = \(\frac{v}{I} = \frac{12}{3} = 4\Omega\)
Which of following functions is performed by manganese IV oxide in the Lenclanche cell?
control of local action
depolarisation of the cell
regulating current flow in the cell
reduction of the internal resistance of the cell
Correct answer is B
No explanation has been provided for this answer.