1) Calculate the terminal voltage for a battery with an internal resistance of 0

Question

1) Calculate the terminal voltage for a battery with an internal resistance of 0.850? and an emf of 7.50V when the battery is connected in series with an 71.0?? resistor.

V=  V

Calculate the terminal voltage for a battery with an internal resistance of 0.850? and an emf of 7.50V when the battery is connected in series with an 710?? resistor.

V=  V

2) What is the internal resistance of a 12.0-Vcar battery whose terminal voltage drops to 9.2Vwhen the starter draws 76

A?

r=   ?

What is the resistance of the starter?

R=  ?

3) A 650?? and a 2100 ?? resistor are connected in series with a 12-V battery. What is the voltage across the 2100

?? resistor?

V2100 =   V

4) Eight identical lights are connected in series across a 110-V line.

What is the voltage across each bulb?

V=  V

If the current is 0.56A , what is the resistance of each bulb?

R=  ?

If the current is 0.56A , what is the power dissipated in each?

P=   W

Explanation / Answer

1)
a)
i = Vo/(r+R) = 7.5/(0.85+71) = 0.1044 A

terminal voltage, v = Vo - i*r = 7.5 - 0.85*0.1044 = 7.41 volts

b)
i = Vo/(r+R) = 7.5/(0.85+710) = 1.055*10^-2 A

terminal voltage, v = Vo - i*r = 7.5 - 0.85*1.055*10^-2 = 7.491 volts

2)

v = Vo - i*r

r = (Vo-v)/i

= (12-9.2)/76

= 0.0368 ohms

let R is Resistance of starter

i = Vo/(r+R)

r+R = Vo/i

R = Vo/i - r

= 12/76 - 0.0368

= 0.121 Ohms



3)

v1 = 12*(2100/(2100+650))

= 9.16 volts

4) v = V0/8 = 110/8 = 13.75 volts

R = v/i = 13.75/0.56 = 24.55 ohms

P = i^2*R = 0.56^2*24.55 = 7.7 watts

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