JAMB - Physics (1979 - No. 16)
A landlord has eight 40W electric light bulbs, four 60W bulbs and two 100W bulb in his house. If he has all the points on for five hours daily and if N.E.P.A. charges 5k per unit, his bill for 30 days is
N5.70
N7.23
N3.65
N8.05
N4.50
Објашњење
Total power = (8 x 40) + (40 x 60) + (2 x 100)
= 760W
Energy(Kwhr) = power x time
= 760 x 10-3 x 150
= 114kwhr.
If, 1kwhr. cost 5k
thus, 114 kwhr. will cost 5 x 114
= N5.70
= 760W
Energy(Kwhr) = power x time
= 760 x 10-3 x 150
= 114kwhr.
If, 1kwhr. cost 5k
thus, 114 kwhr. will cost 5 x 114
= N5.70