Resistance and voltage question?10 points to best answer?

Question

Please look at the diagram below

http://s71.photobucket.com/albums/i159/JogaBonito7/?action=view&current=c1.gif

(1) Calculate the total resistance of the 1 ohm and 4 ohm resistors connected in paralle

(2) Calculate the toal resistance of all the three resistors in the circuit

(3) What would be the reading on the voltmeter?

(4) What would be the reading on the ammeter?

Answer 1

1. Resistors are in parallel, so 1/Rt = 1/R1 + 1/R2

1/Rt = 1.25

Rt = 0.8 Ohms

2. Total resistance  = 0.8 + 9.2 = 10 Ohms

3. P.d. = 12 V as the voltmeter is across the entire load, p.d. across cell = p.d. across total load

4. I = V/R = 1.2 A

Answer 2

(1) Calculate the total resistance of the 1 ohm and 4 ohm resistors connected in paralle    .75 ohms

(2) Calculate the toal resistance of all the three resistors in the circuit

    10 ohms

(3) What would be the reading on the voltmeter?    12 V

(4) What would be the reading on the ammeter?    1.2 A

Answer 3

1) Total resistance of 1 ohm and 4 ohm in parallel

= (1 * 4)/(1 + 4) ohm

= 4/5 ohm

= 0.8 ohm

2) Total resistance of all three = 0.8 ohm + 9.2 ohm = 10 ohm

3) 12 V

4) Current = voltage/resistance = 12/10 A = 1.2 A

Reading on the ammeter = 1.2 A