Problema Solution
The wattage rating W (in watts) of an appliance varies jointly with the square of the current I (in amperes) and the resistance R (in ohms). If the wattage is 8 watts when the current is 0.2 ampere and the resistance is 200 ohms, find the wattage when the current is 0.5 ampere and the resistance is 150 ohms.
Answer provided by our tutors
W = k*R*I^2, where k is constant
W = 8 W when I = 0.2 A and R = 200 ohms
8 = k*200*0.2^2
by solving we find:
k = 1
click here to see the step by step solution of the equation:
W = R*I^2
now we need to find W when:
I = 0.5 A
R = 150 ohms
W = 150*0.5^2
W = 37.5 W
the wattage when the current is 0.5 ampere and the resistance is 150 ohms is 37.5 watts.