Question

9. A cell of emf 4.5V is connected to a junction.
diode whose barrier potential is 0.7V. If the external
resistance in the circuit is 190, then the current in
the circuit is
1) 20mA 2) 2mA 3) 0.2mA 4) 0.02mA
​

Answer 1

Nice question mate

Since the barrier potential is 0.7 V,

Let us keep the potential on diode as 0.7 V

Then the potential across external resistance is 3.8

So V = I R                     (From Ohm's law)

3.8 = I x 190

3800 x 10⁻³ = 190 I

I = 20 mA

Hope this helps !!!

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Answer 2

1) 20mA is the answer for ur question