Which of the following is a good conductor of electricity?
A. Rubber
B. Glass
C. Copper
D. Wood
Answer: Option C
Solution (By JKSSB Mock Tests)
Copper has free electrons, very low resistivity, excellent conductor. Glass, rubber, wood are insulators. Silver best conductor, but copper widely used. Graphite conducts but non-metal.
Explanation:
Planck's constant h = E/ν, so its dimensions are [Energy]/[Frequency] = [ML²T⁻²]/[T⁻¹] = [ML²T⁻¹]. Angular momentum = mvr = M·LT⁻¹·L = [ML²T⁻¹]. Energy = [ML²T⁻²], linear momentum = [MLT⁻¹], force = [MLT⁻²]. Thus, Planck's constant and angular momentum share dimensions. This is a key dimensional match in quantum mechanics.
No comments yet. Be the first to start the discussion!