How to calculate the power rating of a kettle when it is operated from the 240v main supply?
Answers
The governing equation here is
Power = current x voltage or P=IV.
use this and solve
Explanation:
Answer:
Since the above given question is incomplete as the table is not provided, so the table in detail has been provided below:
The table below shows the current in three different electrical appliances when connected to the 240 V mains supply :
Appliance Current
Kettle 8.5 A
Lamp 0.4 A
Toaster 4.8 A
ANSWER:
a) Since current passed is inversely proportional to the resistance of the conductor, so the greatest resistance is possessed by the lamp.
b) i) Due to excessive heating melting down of wire might occur, as large amount of current is drawn by the kettle.
ii) Earthing system is required to maintain safety of a current conducting device which is not here.
c) To calculate power, we apply the formula :
P= VI
P = 240 × 8.5
= 2040 W
d) To calculate the power supply at 120V , we find the value of R [V^2/P], which is = 28.23 ohm [ 240^2/2040]
Now, I= V/R
So, I = 120/28.23
= 4.25 amp