Question

an electric bulbs draws a current of 0.8A and works on 250 volt on the average of 8 hours a day ..
a) find the power consumed by bulb ?
b)if the electric Distribution Company charges rupees 5 for 6 kilowatt hour what is the monthly bill for 60 days ?

Answer 1

⇒ Given

• Current(I) : 0.8 A or $\frac{8}{10}$ Ampere.
• Volt (V) : 250 V
• Time (T) : 8 hours.

⇒ SI Units (To be Taken Care of!)

1. Current = A or Ampere
2. Volt = V or Volts
3. Time = hours.
4. Power = W or Watts

⇒ Formula to be Used :

• $\bold{Power\:=V\:\times\:I}$

⇒Putting values,  

Power = $\bold{250\times\frac{8}{10}}$

Power = $\bold{25\cancel{0}\times\frac{8}{1\cancel{0}}}$

Power = $\bold{25\times\frac{8}{1}}$

Power = $\bold{25\times8}$

Power = $\bold{200\:W}$

∴ Power consumed by bulb in 1 hour = 200Wh

∴Power consumed by bulb in 8 hour = 1600Wh

or Power consumed by bulb in 8 hour = 1.6 kWh

Now,

Power used by bulb in one day = 1.6kWh

Power used by bulb in 60 days = 1.6kWh * 60

Power used by bulb in 60 days = 96kWh

According to Question,

6kWh = ₹ 5

1kWh = ₹ $\bold{\frac{5}{6}}$

∴ 96kWh = ₹ $\bold{\frac{5}{6}\times96}$

∴ 96kWh = ₹ $\bold{\frac{5}{1}\times16}$

∴ 96kWh = ₹ 80

Therefore, Monthly Bill = ₹80.

Thanks!