Current Electricity - Study Mode

[#11] A substance whose molecules consist of dissimilar atoms is called
Correct Answer

(C) Compound

[#12] If a parallel circuit is opened in the main line, the current
Correct Answer

(C) Is zero in all branches

[#13] Out of the following which is an insulating material?
Correct Answer

(D) Paper

[#14] A nichrome wire used as a heater coil has the resistance of 2 Ω/m. For a heater of 1 kW at 200 V, the length of wire required will be
Correct Answer

(D) 20 m

Explanation

Solution: To find the length of the nichrome wire required, you can use the formula: $$P = frac{{V^2}}{{R cdot L}}$$ Where: - $$P$$ is the power (1 kW = 1000 W) - $$V$$ is the voltage (200 V) - $$R$$ is the resistance per meter (2 Ω/m) - $$L$$ is the length of the wire (which we want to find) Let's rearrange the formula to solve for $$L$$: $$L = frac{{V^2}}{{P cdot R}}$$ Now, substitute the values: $$L = frac{{(200, ext{V})^2}}{{1000, ext{W} cdot (2, Ω/ ext{m})}}$$ Calculate this to find $$L$$: $$L = frac{{40000, ext{W}}}{(2000, Ω/ ext{m})} = 20, ext{m}$$

[#15] Ohm's law is not applicable to
Correct Answer

(A) Semiconductors