**UNILAG PHYSICS 2007. POST-UTME**

**1. A box slides down a smooth inclined plane 30m long and 10m high. Determine the speed of the box at the bottom of the plane if it start from rest at the top**

** A. 14m/s**

** B. 140m/s**

** C. 1.5m/s**

** D. 400m/s**

**2. A certain liquid has a specific heat capacity of 3.0kg 0 C. What mass of the liquid may be heated from 20 0 C to 50 0 C by 630J of heat ?**

** A. 4.2g**

** B. 7.0g**

** C. 10.5g**

** D. 11.4g**

**3. A steel rod, 2m long expands by 1mm when heated through 50 0 C. By how much will second steel rods, 1m long, expands when heated, through 25 0 C**

** A. 1/8 mm**

** B. 1/4 mm**

** C. 1/2 mm**

** D. 4 mm**

**4. A coil of resistance 3 ohm has an inductive reactance of 4 ohm. The power dissipated in the coil when connected to an AC supply of 50v rms is**

** A. 100w**

** B. 200w**

** C. 300w**

** D. 400w**

**5. A glass block weighs 25N, when wholly immersed in water, the block of glass appears to weigh 15N. The relative density of glass is therefore.**

** A. 0.40**

** B. 0.60**

** C. 1.67**

** D. 2.50**

**6. W hat upward force must be exerted on a 2kg mass to cause it to rise with an acceleration of 1.5ms -2 ?**

** A. 22.8N**

** B. 2.28N**

** C. 3.20N**

** D. 2.0N**

**7. A stone projected horizontally with a velocity of 15m/s from the top of a building land at a horizontal distance of 60m from the building. The height of the building is**

** A. 120m**

** B. 80m**

** C. 40m**

** D. 20m**

**8. Compute the resultant and the equilibrant of the following system of coplanar concurrent forces: 100N, 240 0 , 100N, 30 0 , 141.4N, 45 0**

** A. 20N at 17 0 , 20N at 197 0**

** B. 151N at 205 0 , 151N at 197 0**

** C. 20N at 197 0 , 20N at 17 0**

** D. 151N at 25 0 , 151N at 205 0**

**9. A n ammeter of resistance R and reading up to 5A, is to be converted to one reading up to 10A. This can be done by connecting**

** A. a resistance R/e in series**

** B. a resistance R in parallel**

** C. a resistance 2R in parallel**

** D. a resistance R in series**

**10. A center of mass 25kg moving with a velocity of 3m/s on a rough horizontal floor is brought to rest after sliding a distance of 2.5m on the floor. What is the coefficient of sliding friction between the crate and the floor ?**

** A. 0.09**

** B. 0.18**

** C. 0.36**

** D. 0.54**

**11. A vibrating wire of length L under tension T emits a note of fundamental frequency f. If a similar wire will emit a note of fundamental length 2f its length and tension could be**

** A. 2L, T/2**

** B. 2L, T**

** C. 2L, 2f**

** D. L/2, T**

**12. Rhythms Broadcasting Station transmit at a frequency of 93.7MH. What is the wavelength of the transmission**

** A. 3.2m**

** B. 32m**

** C. 32.2m**

** D. 32cm**

**13. Two inelastic objects of masses 16kg and 4kg move in opposite directions towards each other with velocities of 3m/s and 5m/s respectively. Find the resultant velocity BV on collision if they are stuck together**

** A. 1.4 m/s**

** B. 14 m/s**

** C. 140 m/s**

** D. 0 m/s**

**14. A jack screw has a lever arm of 45cm and a pitch of 0.5cm. If its efficiency is 30%, what force F is required to lift a load w of mass 1200kg?**

** A. 6.0N**

** B. 69N**

** C. 0.69N**

** D. 690N**

**15. A body of mass 20kg, moving with uniform acceleration, has an initial momentum of 200kgm/s after 10s, the momentum is 300kgm/s. Wat is the acceleration of the body?**

** A. 0.5ms -2**

** B. 5ms -2**

** C. 25ms -2**

** D. 50ms -2**

**16. A n electron in orbit the nucleus made 300 revolutions per minute, what is the angular velocity of the electron ?**

** A. 300(22/7) rad/s**

** B. 30(22/7) rad/s**

** C. 10(22/7) rad/s**

** D. 3(22/7) rad/s**

**17. A battery of emf 24v has an internal resistance 12 ohm. The current draw is**

** A. 3/8A**

** B. 1/2A**

** C. 2A**

** D. 8A**

**18. In the radioactive series**

** 235 –> 235 –> 234 –> 231**

** J K L M**

** 92 93 91 92**

** The particles emitted are respectively**

** A. beta, alpha, beta**

** B. beta, beta, alpha**

** C. alpha, beta, alpha**

** D. alpha, alpha, beta**

**19. I f the pressure in a confined liquid is changed at any point, the change as transmitted equally to all points in the liquid. This principle is called**

** A. Archimede’s principle**

** B. Flotation principle**

** C. Pascal’s law**

** D. Boyle’s law**

**20. A metal having a work function of 5.76eV is illuminated with a radiation of 7.88eV. The kinetic energy of the electrons emitted from the metal surface is**

** A. 13.64eV**

** B. 6.82eV**

** C. 4.24eV**

** D. 2.12eV**

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