Question
Answer problems please
A small bulb is rated at 7.50 W when operated at 125 V. The tungsten filament coefficient of resistivity a = 4.50 times 10-3 t degree C. When the filament is hot and glowing, its temperature is seven times room temperature (20 degree C).What is the resistance of the filament (in ohms) at room temperature?234 1 350 2 080 4 5305 630What is the current in the 10 Ohm. resistor ?0.60 A 3.0 A1.2 A2.4 A0.30 AThe circuit below contains 3 100-W light bulbs and a capacitor. The emf is is 110 V. Which light bulb(s) is(are)brightest?(Assume the capacitor is fully charged.)ABCA and B All three are equally bright.
Explanation / Answer
1) b.......R 1 = R2 /(1+alfa*dT )= (V^2/P) / (1+alfa*dT)
2) b......Reff = (1/((1/10)+(1/5)+(1/5))) + 3 = 7 .......i E/Reff= 3 A
3) d