Answer:
See the answers below.
Explanation:
1
The data of 100W means power, and the other data of 220V means voltage, that is to say that bulb serves to work at a voltage of 220V100W datum means power.
J means work that is given in Joules [J], we must remember that power is defined as the relationship between work at a certain time, therefore we can determine work by means of the following expression.
[tex]P=W/t\\[/tex]
where:
P = power [Watt]
W = work [J]
t = time [s]
[tex]W=P*t\\W=100*5[hr]*[\frac{3600s}{1hr} ]\\W=1800000[J] = 1.8[MJ][/tex]
Now the electric cost.
[tex]0.1[kW]*5[hr]*55\frac{LL}{1kwhr} =27.5[LL][/tex]
2
We know that power is defined as the product of voltage by resistance.
[tex]P=V*I[/tex]
where:
P = power [W]
V = voltage [V]
I = current [amp]
[tex]I=P/V\\I=1500/220\\I=6.82[amp][/tex]
3
The voltage can be calculated by means of ohm's law, which tells us that the voltage is equal to the product of resistance by the current.
[tex]V =I*R[/tex]
where:
V = voltage [V]
I = current = 20 [mA] = 0.02 [A]
R = resistance = 20 [kΩ] = 20000 [Ω]
Now replacing:
[tex]V = 0.02*20000\\V = 400 [V][/tex]
4
According to the figure we see that when the current is equal to 10 [mA] the voltage is equal to 1 [V]. With these two values, we can use ohm's law and find the value for the resistance.
[tex]V = I*R\\R = V/I\\R = 1/0.01\\R =100 [ohm][/tex]
