Question

4. There are two resistances of 3 ohm and 5 ohm. Which
of the resistances will be hotter, if the two resistances joined :
(i) in series and
(ii) in parallel are connected to a cell ?
​

Answer 1

Answer:

in series 3 ohm whereas in parallel 5 ohm

Answer 2

Answer:

i) it depends on the position of resistor and amount of current

ii) 5 Ohm resistor

Explanation:

Heat produced is directly proportional to the square of current ( i ) and the resistance(R) of the medium.

Heat =  I²R

⇒ Heat α R

⇒ Heat α Current (I)

i) in series connection, the resistor that gets more current and with more resistance will produce more heat. Well at this point, it  comes down to numerical as it depends on two different variables.

ii) in parallel both the resistor are subjected to same amount of current, so it depends on the resistance only, therefore resistor with high resistance (5 Ohm) will produce more heat.

Note:

Here, u must not  take Heat = V²/R and so conclude that Heat is inversely proportional to R as V = IR.

Hope this helps You!!!

:)