The filament of a certain lamp has a resistance that increases linearly with temperature. when a constant voltage is switched on, the initial current decreases until the filament reaches its steady-state temperature. the temperature coefficient of resistivity of the filament is 43 times 10^-3 k^-1. the final current through the filament is one- eighth the initial current. what is the change in temperature of the filament?

a.30100 k
b.378 k
c.1627 k
d.814 k
e.1162 k

162.8 K

Explanation:

initial current = io

final current, i = io/8

Let the potential difference is V.

coefficient of resistivity, α = 43 x 10^-3 /K

Let the resistance is R and the final resistance is Ro.

The resistance varies with temperature

R = Ro ( 1 + α ΔT)

V/i = V/io (1 + α ΔT )

8 = 1 + 43 x 10^-3 x ΔT

7 = 43 x 10^-3 x ΔT

ΔT = 162.8 K

Thus, the rise in temperature is 162.8 K.

current and voltage can both be different in different parts of a circuit so it matters where you place the ammeter and voltmete

that would be because of both gravity and friction. so     c