Q1(a)(i)What is the S.I unit of work?


Q1(a)(ii)A body of mass 1 Kg falls from a height of 5 m. How much energy does it possess at any instant (take g = 9.8m/s²) ?


Q1(a)(iii)When a body moves in a circular path , how much work does it do?


Q1(b)The diagram given below shows the use of a lever.

(i)State the principle of moments as applied to the above lever.


(ii)Give an example of this class of lever.


(iii)If FA=10 cm,AB=500 cm, calculate the minimum effort required to lift the load.


Q1(c)(i)State Archimedes' Principle.


Q1(c)(ii)A man first swims in sea water and then in river water.
1. Compare the weight of sea water and river water displaced by him.
2. Where does he find it easier to swim and why?


Q1(d)(i) The graph below represents a cooling curve for a substance being cooled from a higher temperature to a lower temperature.

1. What is the boiling point of the substance?
2. What happens in the region DE?
3. Why is the region DE shorter than the region BC?


Q1(d)(ii)At what approximate temperature will water boil in a pressure cooker?


Q1(e)The diagram below shows a ray of white light AO incident on a rectangular glass block, which is silvered at one surface. This ray is partly refracted.

(i) Copy the diagram and trace the path of the refracted and reflected ray. Show at least two rays emerging from the surface PQ.


(ii)How many images are formed in the above case? Which image is the brightest?


Q1(f) The diagram below shows a students vision from his near point.

(i) What defect is he suffering from?


(ii) State one cause for the occurrence of this defect.


(iii) Copy the diagram and complete to show how this defect is corrected.


Q1(g)(i)The following diagram shows two straight wires carrying current.Copy the diagram and draw the pattern of lines of force around them and mark their directions.

(ii)How is galvanometer converted to
1. an ammeter
2. a voltmeter


Q1(h)(i) A refrigerator is marked 80W and 220V
1. How much energy does it consume in one day if on an average it is used for 20 hrs. a day?
2. What is likely to happen if the voltage drops to 50V?


Q1(h)(ii)Score off the incorrect words and write correctly the following:
In wiring a three-pinplug , the brown sleeved wire is connected to the neutral/live pin and the green/blue sleeved wire is connected to the metal body of the appliance.


Q1(i)X-rays are produced in a coolidge tube when cathode rays are made to strike a target.
(1).Why is the anode of the tube heated  up at the the time of emission of X-rays?
(2). How is the strength and penetrating power controlled?
(3) Which of the soft and hard X-rays has a longer wavelength and which has higher penetrating power?


Q1(j)(i)State the transformation of energy taking place in a
1. Loud speaker
2. Washing machine


Q1(j)(ii)An a particle absorbs an electron. What does it change to?


Q1(j)(iii)A fusion reaction is represented as follows
₁H² + ₁H²-----> ₂He⁴ + x.
Identify x.


Q2(a)A bullet of mass 50 g is moving with a velocity of 500 m/s. It penetrates 10 cm into a still target and comes to rest.
1. Calculate the K.E possessed by the bullet.
2. The average retarding force offered by the target.


Q2(b)The diagram alongside shows a system of 5 pulleys.

1.Copy the diagram and complete it by drawing a string around the pulleys. Mark the position of load and effort.
2. If the load is raised by 1 m, through what distance will the effort move?


Q2(c)A flat - bottomed test-tube floats upright  with some lead shots, on the surface of water 10 cm of its length immersed. The tube and the lead shots were found to weigh 20 g, when weighed in a beam balance.The same test-tube when floated in Kerosene was found to float with 12 cm immersed.
1. What mass of water does it displace when floated on water?
2. What is the area of cross-section of the tube?
3. calculate the R.D of Kerosene.


Q3.(a)Explain why bottled soft drinks are more effectively cooled by cubes of ice than by iced water.


Q3(b) 10 g of ice at 0^oC absorbed 5460 J of heat to melt and change to water at 50^oC.Calculate the specific latent heat of fusion of ice. [Specific heat capacity of water is 4200 J/Kg/^oC]


Q3(c) In an experiment to determine the specific latent heat of vaporisation of steam 'L' , the following measurement were taken :
Mass of calorimeter + stirrer = x Kg
Mass of water = y Kg
Initial temperature of water = t₁^oC
Final  temperature of mixture = t₂^oC
(Given S.H.C. of calorimeter and water are S₁ and S₂ respectively)
Express 'L' in terms of the above data.


Q4(a)(i) Differentiate between "forced vibration" and "resonance".


(ii) How does frequency and amplitude affect a musical sound?


Q4(b)Two musical notes of the same pitch and loudness are played on a violin and a piano. Their waveforms are as shown in the figures .

Explain why the wave patterns are different.


Q4(c)(i)An electromagnetic wave has a frequency of 500 MHz and a wavelength 60 cm. Calculate the velocity of the wave. Name the medium through which it is travelling.


(ii) A wave has a wavelength of 0.01 Å. Name the wave.


Q5(a)What is meant by
(i)Critical angle
(ii)Total internal reflection?


Q5(b)(i)Draw a diagram to show that white light can be split up into different colors.


(ii)Draw another diagram to show how the colors can be combined to give the effect of white light.


(iii) How would you show the presence of ultra-violet and infra-red rays in the spectrum?


Q5(c) When yellow paint and blue paint are mixed we get green color. When yellow light and blue light are mixed white light is obtained. Give reasons for the observations mentioned.


Q6(a)(i) State Ohm's law.


(ii) State the factors that alter the resistance of a conductor.


Q6(b)The following circuit diagram shows three resistors 2W, 4W and RW connected to a battery of emf 2V and internal resistance 3W. A main current of 0.25 ampere flows through the circuit.

 
(i) What is the P.D across the 4W resistor?


(ii) Calculate the P.D across the internal resistance of the cell.


(iii) What is the P.D across the RW or the 2W resistor?


(iv) Calculate the value of R.


Q6(c) State two ways of increasing the speed of rotation of a D.C motor.


Q7(a)(i)Draw a neat labeled diagram of a hot cathode ray tube.


(ii) What is the effect on the beam particles if
1. a hotter filament is used
2. the anode voltage is increased?


(iii) Name one device in which the cathode ray tube is used.


Q7(b) State the factors that affect the rate of emission of electrons in a photoelectric cell.


Q7(c)(i)A thorium isotope ₉₀Th²²³ undergoes an a-decay and changes into Radium. What is the atomic number and mass number of the radium produced?


(ii)If the radium undergoes a further disintegration and emits two b particles, represent this reaction in the form of an equation.


(iii)What is the source of energy released during the decay?