Which of the following is used as a moderator in nuclear reactor?
A. Uranium
B. Graphite
C. Cadmium
D. Boron
Answer: Option B
Solution (By JKSSB Mock Tests)
Graphite, heavy water (D₂O), beryllium are moderators. Cadmium and boron are control rods (absorb neutrons). Uranium is fuel. Moderator slows neutrons.
Explanation:
Resistance of a bulb is R = V^2 / P. The 60W bulb has a higher resistance than the 100W bulb. When connected in series, the exact same current (I) flows through both. The power consumed (which determines brightness) is given by P = I^2R. Since the 60W bulb has higher resistance (R), it consumes more power and glows brighter.
Explanation:
Polarization requires transverse waves (oscillations perpendicular to propagation). Light, radio waves, X-rays are electromagnetic transverse waves and can be polarized. Sound waves in air are longitudinal (oscillations parallel to propagation) and cannot be polarized. Memory tip: 'Polarization ⇒ transverse waves only; sound is longitudinal ⇒ no polarization'. This wave property question tests understanding of wave types, frequently examined in competitive exams. Always classify waves as transverse/longitudinal to determine polarization possibility; this is a common conceptual trap.
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