Physics - Study Mode

[#731] Which one of the following is an ohmic conductor?
Correct Answer

(D) Silver

Explanation

Solution: An ohmic conductor is defined as a two-terminal device in which the voltage or current characteristics have a straight line passing through the origin. Silver, copper wire, metals are the examples of ohmic conductors.

[#732] What is the effective resistance (in Ω) of two resistors 20 Ω and 30 Ω connected in parallel?
Correct Answer

(B) 12

Explanation

Solution: according to rules

1/R = 1/R1 + 1/R2 (for parallel)

=1/20 + 1/30

=12 ohm

[#733] Which elements are malleable and good conductors of electricity?
Correct Answer

(A) Tin and silver

Explanation

Solution: The elements which will be malleable (thin sheets) and good conductors of electricity has to be a metal. Tin and Silver is correct answer.

[#734] What is the resistance (in ohm) of an electrical component if a current of 0.1 A passes through it on application of 5 V of potential difference across it?
Correct Answer

(C) 50

[#735] If electric resistance is to be decreased, then the number of resistances should be connected in ________
Correct Answer

(B) Parallel

Explanation

Solution: Resistors are in parallel when each resistor is connected directly to the voltage source by connecting wires having negligible resistance. Each resistor thus has the full voltage of the source applied to it.When resistors are connected in parallel, more current flows from the source than would flow for any of them individually, so the total resistance is lower. Each resistor in parallel has the same full voltage of the source applied to it, but divide the total current among them.