WAEC Physics Past Questions & Answers - Page 6

L1=50.
T1 = 30 + 273 = 303k
Linear expansivity =  1.9 x 10\(^{-5}\)

L2 = 50.29

Temp rise= ?

L2 - L1 = 50.29 - 50 = 0.29
Linear expansivity = \(\frac{L2-L1}{L1(T2-T1)}\)

1.9 x 10\(^{-5}\) = \(\frac{0.29}{50*(T2 - 303)}\)

1.9 x 10\(^{-5}\) * 50 (T2 - 303) = 0.29

T2 = \(\frac{0.29}{50 * 1.9 * 10^{-5}}\) + 303

T2 = 152.6 °C

All electromagnetic waves are:

• transverse waves; can travel through a vacuum ;
• travel at exactly the same speed in a vacuum, the speed of light, 300,000,000 m/s.
• transfer energy from one place to another;
• can be reflected;
• can be refracted .
• The oscillations of and are perpendicular to each other and are in the same phase.

\(\frac{10.5-0}{30-0}\) = \(\frac{c-0}{100-0}\)

\(\frac{10.5}{30}\) = \(\frac{c}{100}\)

cross multiply:

10.5 * 100 = 30c

35.0 ºC = c

speed of the sound wave = \(\frac{distance * 2}{time}\)

= \(\frac{408 * 2}{2.4}\)

: speed of the sound wave = 340 ms\(^{-1}\)

In physics, a transverse wave is a wave whose oscillations are perpendicular to the direction of the wave's advance.

This is in contrast to a longitudinal wave which travels in the direction of its oscillations. Water waves are an example of transverse wave.

No explanation has been provided for this answer.

Gamma rays are produced in the disintegration of radioactive atomic nuclei and in the decay of certain subatomic particles.

Gamma radiation is emitted by excited nuclei or other processes involving subatomic particles;

it often accompanies alpha or beta radiation, as a nucleus emitting those particles may be left in an excited (higher-energy) state.

de broglie wavelength formula in terms of kinetic energy:

 λ = \(\frac{h}{\sqrt{2mE}}\) 

 λ = \(\frac{6.6 *10^{-34}}{\sqrt{2 *9.1*10^{-31} *100 }}\)

 λ = 5.50 x 10\(^{-14}\)m

Alpha particles are highly ionising because of their double positive charge, large mass (compared to a beta particle) and because they are relatively slow.

They can cause multiple ionisations within a very small distance.

And the gamma radiation has the least ionising power.

If the dominant impurity atoms are ACCEPTOR type in the semiconductor, it will have a majority of holes over the electrons [p-type]