Physics Past Questions And Answers
The current through a resistor in an a.c circuit is given as 2 sin wt. Determine the d.c. equivalent of the current
- A. A/√2
- B. 2/√A
- C. 2 A
- D. √2 A
Which of the following has the lowest internal resistance when new?
- A. Leclanche cell
- B. Daniell cell
- C. Torch battery
- D. Accumulator
It is known that a neutron exists in a light atomic nucleus Which of the following also exists in the nucleus?
- A. An electron
- B. A β - particle
- C. β - particle
- D. proton
(a)(i) Explain what is meant by a machine (ii) Define the terms: mechanical advantage, velocity ratio and efficiency as applied to a machine. Derive the equation connecting the three terms.
(b) Explain why the efficiency of a machine is usually less than 100%
(c) A screw jack whose pitch is 4.4mm is used to raise a body of mass 8000 kg through a height of 20cm. The length of the tommy bar of the jack is 70cm. If the efficiency of the jack is 80%, calcuate the: (i) velocity ratio of the jack; (ii) mechanical advantage of the jack (iii) effort required in raising the body, (iv) work done by the effort in raising the body \((g = 10ms^{-2}; \pi = \frac{22}{7}\))
View Discussion (0)WAEC 1993 THEORYWhich of the following actions is necessary in order to tune a string to produce a note of an octave higher than its fundamental?
- A. doucling the length of the string
- B. reducing the tension by half
- C. reducing the mass per unit length
- D. increasing the tension four times
In the hydraulic press, the force F applied is related to the diameter d of the cylinder by
- A. F \(\alpha\) d\(^2\)
- B. F \(\alpha\) d
- C. F \(\alpha\) d\(^{-1}\)
- D. F \(\alpha\) d\(^{-2}\)
An object weighs 60.0N in air, 48.2N in a certain liquid X, and 44.9N in water, Calculate the relative density of X
- A. 3.300
- B. 1.279
- C. 0.932
- D. 0.782
A pipe of length 45cm is closed at the end. Calculate the fundamental frequency of the sound wave generated in the pipe if the velocity of sound in air is 360ms-1 [Neglect end correction]
- A. 5.5Hz
- B. 148.5Hz
- C. 200.0Hz
- D. 550.0Hz
State;
(a) the difference between plane polarized light and ordinary light;
(b) two uses of polaroids
View Discussion (0)WAEC 2007 THEORYTwo bodies have masses in the ratio 3:1. They experience forces which impart to them acceleration in the ratio 2:9 respectively. Find the ratio of forces the masses experienced.
- A. 1 : 4
- B. 2 : 1
- C. 2 : 3
- D. 2 : 5