The resistance of a resistor is kept constant and the p.d. difference across its two ends is decreased to half of its former value. State the change that will occure in the current through it.
Answers
Answered by
114
hello,
let the current be i
let the resistance be r
let the p.d. be v
by ohm's law
v=ir
i=v/r................................1
now resistance is kept at constant
v is now v/2 and let the current be I
therefore,
v/2=Ir
I=v/2r
but from 1 we see that v/r is initial current
therefore,I=i/2
hence the current also decreased by half of its former value
OR
we know that current is directly proportional to p.d.
hence if current decreases p.d. will also decrease with the same amount
therefore p.d. is decreased by 1/2 current will also be decreased by 1/2
let the current be i
let the resistance be r
let the p.d. be v
by ohm's law
v=ir
i=v/r................................1
now resistance is kept at constant
v is now v/2 and let the current be I
therefore,
v/2=Ir
I=v/2r
but from 1 we see that v/r is initial current
therefore,I=i/2
hence the current also decreased by half of its former value
OR
we know that current is directly proportional to p.d.
hence if current decreases p.d. will also decrease with the same amount
therefore p.d. is decreased by 1/2 current will also be decreased by 1/2
Answered by
28
Current is 1/2 the original value
Similar questions