Question 4621:

• NECO 2009

Which of the following pairs of phenomena helps in the resolution of the wave-particle paradox of matter?

A. Compton effect and thermionic emission
B. Electron diffraction and refraction
C. Emission and absorption of light
D. Interference and polarization
E. Reflection and photoelectric effect

Question 4622:

• NECO 2009

Which of the following phenomena is responsible for the spherical shape of soap bubbles?

A. Adhesion
B. Capillarity
C. Cohesion
D. Osmosis
E. Surface tension

Question 4623:

• NECO 2009

A plane progressive wave is represented by the equation y = 0.2sin (200πt - 0.5.x) where x and y are measured in cm and t in s. What is the frequency of the wave?

A. 0.5Hz
B. 4.0Hz
C. 10.0Hz
D. 100.0Hz
E. 200.0Hz

Question 4624:

• NECO 2009

A transformer has an efficiency of 92.5%. the ratio number of turns in the primary coil to that in the secondary coil is 128 : 45. If the current passing through the secondary coil is 9.0A, calculate the current passing through the primary-coil.

A. 2.93A
B. 3.16A
C. 3.42A
D. 25.60A
E. 27.68A

Question 4625:

• NECO 2009

An immersion heater is rated 1500W. How long does it take the heater to raise the temperature of 1 kg of water by 30°C? (Assume heat lost to the surrounding is negligible, Specific heat capacity of water 4200Jkg^-1K^-1)

A. 84s
B. 112s
C. 130s
D. 168s
E. 280s