Homework Help

(Electricity) How do I find the current for L1(lamp 1)? And the voltage for R1 and the...

user profile pic

tjjavid | Student, Undergraduate | Honors

Posted June 15, 2013 at 1:17 PM via web

dislike 0 like

(Electricity)

How do I find the current for L1(lamp 1)?

And the voltage for R1 and the resistance for R1

Images:
This image has been Flagged as inappropriate Click to unflag
Image (1 of 1)

Tagged with electricity, science

2 Answers | Add Yours

user profile pic

llltkl | College Teacher | Valedictorian

Posted June 15, 2013 at 1:59 PM (Answer #1)

dislike 1 like

Ask one question at a time. As per the prevailing rules I am to answer only one question at a time.

E.M.F. of the circuit = 9 Volts.

In order to find the total effective resistance of the circuit, the internal resistance of the light bulb has to be worked out first.

For the light bulb `L_1` , ∆V = 6V, I = 0.5A, therefore, R = ∆V/I = 6/0.5 = 12 ohms.

Total effective resistance of the circuit = (`R_1` +12) ohms (ignoring the internal resistance of the 9V cell).

Therefore, current passing through the light bulb `L_1` (and also through the resistor `R_1` )

= `9/(R_1+12)` Amperes.

=> answer.

 

 

Sources:

user profile pic

llltkl | College Teacher | Valedictorian

Posted June 22, 2013 at 3:58 PM (Answer #2)

dislike 1 like

I'm Sorry! The power of the light bulb L_1 is given, which is 0.5 W.

Corrigendum:

Watt = Volt × Current

0.5 = 6 × i

`rArr` i = 0.5/6 = 0.083 Amperes(approx).

Therefore, the current through the bulb is 0.083 amperes.

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes