Question

Which of the following can be used in a tester along with a battery to detect a weak current in the circuit?
(1) LED only
(2) A coil wounded over a compass needle only
(3) Bulb of 100 W only
(4) Either LED or a coil wounded over a compass needle​

Answer 1

$\huge\green{\boxed{Hi Curious !}}$

Which of the following can be used in a tester along with a battery to detect a weak current in the circuit?

Answer

(1) LED only ☑️

$\huge\bold\red{<u>Explanation</u>}$

Lead pieces are attached to an LED.

One lead is longer than the other leads.

While connecting LED in the circuit, the long head is connected to the +ve terminal of the battery in all cases.

☞ ʜᵃᵛᵉ ᴀ ɢᵒᵒᵈ ᴅᵃʸ ☜

ʕ•ٹ•ʔ ᵇʳᵃⁱⁿˡʸ_ᵗʳᵉᵃˢᵘʳᵉ!

Answer 2

Only LED bulb can be used in a tester and with the battery to detect a weak current in a circuit. (option 1)

- A weak current cannot show any difference in a coil wounder over a compass needle or a 100 W bulb because these things need a strong current flow for their operation.

- That's why options 2,3,4 are eliminated for the detection of a weak current.

- Now,a small LED bulb can glow with the help of small amount of electricity and that's why we should use only the LED in this case.