Question

What is the resultant resistance when a number of resistances are connected in series .

Answer 1

if the resistances are connected in series the resistances will be added

req=r1+r2 and so on

but if it is in parallel

then

req=1/r1+1/r2 and so on

hope it helps mate

Answer 2

When resistances are connected in series then the resultant resistance is the sum of all individual resistances.

Ie,

Req = R1 + R2 + R3 + .....+ Rn.

✔Proof :

▶In series all resistance get equal current. And sum of potential difference of individual resistance is equal to the total potential difference of the main cell or battery.

So,

▶V = v1 + v2 + v3 +.... + vn

▶IReq = IR1 + IR2 + IR3 + ...... + IRn

▶I R eq = I(R1 + R2 + R3 +.......+ Rn)

▶R eq = R1 + R2 + R3 + ....... +Rn

In parallel connection:

1/R eq = 1/R1 + 1/R2 + 1/R3 + ....... + 1/Rn