Question

Find the effective resistance when resistors 10 and 15 Q are
connected in (i) series, (ii) parallel. only for 9th std questions​

Answer 1

Solution :-

As per the given data,

• R 1 = 10 Ω
• R 2= 15 Ω

Series

When n no of resistors are connected in series  with each other the equivalent resistance of the combination is given by ,

→ Rs = R 1 + R 2 + R 3 .... Rn

hence ,

→ Rs = R 1 + R 2

Now let us substitute  the given values in the above equation ,

→ Rs = 10 + 15

→ Rs = 25 Ω

The equivalent resistance of the combination is 25 Ω

Parallel

When n no of resistors are connected in parallel  with each other the equivalent resistance of the combination is given by ,

→ 1 / Rp = 1 / R 1 + 1 / R 2 +1 / R 3 .... 1 / Rn

hence ,

→ 1 / Rp = 1 / R 1 + 1 / R 2

Now let us substitute  the given values in the above equation ,

→ 1 / Rp = 1 / 10 + 1 / 15

→ 1 / Rp = 3 + 2 / 30

→ 1 / Rp = 5 / 30

→ Rp = 30 / 5

→ Rp = 6 Ω

The equivalent resistance of the combination is 6Ω