2009 - JAMB Physics Past Questions and Answers - page 3

¹/_R = ¹/_R1 + ¹/_R2 = ¹/₃ + ¹/₆

= ³/₆

∴ R = ⁶/₃ = 2

E = I(R + r) = 4(2 + 0) = 8v

V =

√ (v₁ + v₂)² + V_R² 

V =

√ (40 + 110)² + 80² 

V =

√ (-70)² + 80² 

=

√ 4900 + 6400 

=

√ 11300 

= 106.3v

Correct Answer: Option E

        Comparing y = 10Sin\( (1000\pi t - \frac{\pi x}{34} ) \\

\text{With } y = a \text{Sin }(net - kx)\

K = \frac{\pi}{34}, \text{and phase difference}\

J = KAC = \frac{\pi}{34} \times 1.53rad.\

\text{But} \pi rad = 180^0 \

\text{Therefore } \frac{1.53rad}{34} = \frac{1.53 \pi}{34} \times \frac{1}{\pi} \times 180^0 \

=8.1^0 )

Correct Answer: Option E

        The person's image distance v will be at the distance of 0.1m = 10cm for him to see objects at a distance of u.F = 5.0cm<br />

( \frac{1}{v} + \frac{1}{u} = \frac{1}{f} \implies \frac{1}{10} + \frac{1}{u} = \frac{1}{5} \

\frac{1}{u} = \frac{1}{5} - \frac{1}{10} = \frac{2-1}{10} = \frac{1}{10} \

\text{therefore } u = 10cm = 0.1m )

Of all the instruments used in measuring length,the micrometer screw gauge has the highest reading accuracy (0.01 mm), and is therefore used in measuring very small length such as diameter of a small ball bearing, and thickness of a piece of paper.

Acceleration = (AV)/At = (V₂) - U₁)/t₂ - t₁ = (35 - 15)/20 - 10 = (20)/10 = 2m5^-2

At maximum height, the final velocity, v = 0

thus from v = u + at

      0 = u - at <br />

    ∴ U = at = 10 x 4 = 40 mls

Simple harmonic motion is the motion of a body whose acceleration is directed towards a fixed point and is directly proportional to its displacement from point.

Power = (work done)/time taken = (mgh)/t

    = (750 x 10 x 90)/60 = 11250w = 11.25kw