If the length of a simple pendulum is made four times, its time period becomes:
B. Double
T = 2π√(L/g); T ∝ √L, so 4L gives 2T.
Resistors of 6 Ω and 3 Ω are connected in parallel. What is the equivalent resistance?
D. 2 Ω
R = (6×3)/(6+3) = 18/9 = 2 Ω.
A wave has frequency 50 Hz and speed 340 m/s. What is its wavelength?
A. 6.8 m
λ = v/f = 340/50 = 6.8 m.
A 10 μF capacitor is charged to 100 V. How much energy is stored in it?
B. 0.05 J
U = ½CV² = ½ × 10×10⁻⁶ × 10⁴ = 0.05 J.
A ball is thrown vertically upward at 20 m/s. Taking g = 10 m/s², what maximum height does it reach?
C. 20 m
h = v²/2g = 400/20 = 20 m.