Grade 10Electric Current
H=V2/R
=>H α 1/R, Potential Difference and time remaining constant
Therefore, heat produced is more if R is less.
R=ρl/A =>R α 1/A
Therefore, heat produced is more if A is more. [Because, R decreases if A increases which in turn produces more heat.]
More heat would produce more light.
Therefore more A would produce more light.
Then why are filaments used in bulb made thin i.e. their A is made less?
Notations:
A-area of cross section
R-Resistance
H-Heat
Ρ-restivity
H=V2/R
=>H α 1/R, Potential Difference and time remaining constant
Therefore, heat produced is more if R is less.
R=ρl/A =>R α 1/A
Therefore, heat produced is more if A is more. [Because, R decreases if A increases which in turn produces more heat.]
More heat would produce more light.
Therefore more A would produce more light.
Then why are filaments used in bulb made thin i.e. their A is made less?
Notations:
A-area of cross section
R-Resistance
H-Heat
Ρ-restivity
