Answer :
Answer:
t=17 min
Explanation:
Given that
E= 10 V
I=10 A
Internal resistance Rin= 0.08 Ω
E= I.R(net)
E=I(R+r)
10 = 10 (R+0.08)
R= 1 - 0.0 8 = 0.02 Ω
R= 0.98 Ω
So the heat given as
Q=I²Rt
Q=10² x 0.98 x t
Q= 98 t J
Given that Q= 100 KJ
98 t = 100 x 1000 J
t= 100 x 1000/98 sec
t=17 min
The time to boil a cup of water using the device by David If the energy required is 100 kJ is 17 minutes.
What is the Ohm's law?
Ohm's law states that for a flowing current, the potential difference of the circuit is directly proportional to the current flowing in it. Thus,
[tex]V\propto I[/tex]
Here, (V) is the potential difference and (I) is the current.
It can be written as,
[tex]V=IR[/tex]
Here, (R) is the resistance of the circuit.
A device for heating a cup of water in a car connects to the car's battery, which has an emf E = 10.0 V and an internal resistance rint = 0.08 Ω .
The heating element that is immersed in the cup of water is a resistive coil with resistance R. The total resistance is,
[tex]R_n=R+0.08\rm \; ohm[/tex]
The value of current in ammeter into the circuit is 10.0 A when the device is connected to the car's battery. Put these values in the ohm's law.
[tex]10=10(R+0.08)\\R=0.98\rm\; ohm[/tex]
The heat generate in a circuit in time (t) can be given as,
[tex]Q=I^2Rt[/tex]
The energy required is 100 kJ. Thus, by the above expression,
[tex]100\times 10^3=(10)^2(0.92)t\\t=1020.41\rm\; sec\\[/tex]
[tex]t=1020.41\times\dfrac{1}{60}\rm\; min\\t=17\;min[/tex]
Thus, the time to boil a cup of water using the device by David If the energy required is 100 kJ is 17 minutes.
Learn more about the Ohm's law here;
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