Simple pendulum period T = 2π√(l/g). If length quadrupled, T becomes:
A. Same
B. Double
C. Half
D. Four times
Answer: Option B
Solution (By JKSSB Mock Tests)
T ∝ √l. If l' = 4l, T' = √4 × T = 2T. Period doubles when length quadruples. Memory aid: 'Pendulum: T ∝ √l; 4× length ⇒ 2× period'. Proportional reasoning frequently tested in competitive oscillations sections.
Explanation:
TIR: denser→rarer medium AND incidence angle > critical angle. Glass to air satisfies first condition; angle must exceed θ_c. Memory aid: 'TIR: n₁>n₂ AND i>θ_c; direction matters'. Optics condition frequently tested in competitive exams.
Explanation:
LED (Light Emitting Diode) emits light when forward biased, due to recombination of electrons and holes. Efficient, long life. Used in displays, lighting. Laser is Light Amplification by Stimulated Emission of Radiation.
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