SS 2 Physics Third Term Examination

   THIRD TERM

Examination malpractices may lead to a repeat of the subject or suspensions don’t be involved.   

SUBJECT: PHYSICS           

CLASS: SS 2       

DURATION ; 2HRS

SECTION A

INSTRUCTION: Attempt all question in this section.

1. A transparent rectangular block 3.0cm thick is placed on the letter ‘A’ written on a white cardboard. When the letter was viewed from the top of the glass block, it appeared to be 2cm. calculate the refractive index of the block (a) 3/2 (b) 5/3 (c) 1/2 (d) 3/2
2. The velocities of light in air and glass are 3.0 x108 m/s and 1.8 x108 m/s respectively. Calculate the sine of the angle of incidence that will produce an angle of refraction of 300 for a ray of light incident on glass A 1.2  B 1.0  C 0.8  D 0.6 
3. The horizontal floor of a water reservoir appears to be 1.0m deep when viewed vertically from above. If the refractive index of water is 1.35, calculate the real depth of the reservoir (a) 2.35m (b) 1.35m (c) 1.00m (d) 0.35m
4. A beam of light travelling through air at 3.0×108m/s enters a pool of water of refractive index 4/3, what is its speed as it travels through water (a) 2.25×108ms-1 (b) 3.25×108ms-1 (c) 4.25×108ms-1 (d) 5.25×108ms-1

Use the information below to answer questions 5, 6 and 7

The angle of incidence of a narrow beam of light on a side of an equilateral triangular prism is 480. Calculate the:

1. Angle of minimum deviation (a) 360 (b) 300 (c) 450 (d) 600
2. Angle of refraction (a) 360 (b) 300 (c) 450 (d) 600
3. Refractive index of the material of the prism (a) 1.50 (b) 1.26 (c) 0.55 (d) 2.0
4. A ray of light is incident normally on an air-glass interface. What is its angle of refraction? (a) 900 (b) 600 (c) 300 (d) 00
5. The image formed by a converging lens is 3 times as tall as the object. If the focal length of the lens is 12cm, calculate the distance of the image from the object (a) 16cm (b) 48cm (c) 32cm (d) 64cm
6. Which of the following correctly describe the image formed by a diverging lens? (a) Diminished, erect and virtual (b) Diminished, inverted and real (c) Magnified, erect and virtual (d) Magnified, inverted and real
7. The image formed on the retina of a human eye is (a) virtual and diminished (b) real and inverted (c) erect and real (d) inverted and virtual
8. Long sight is corrected by one of the following (a) diverging lens (b) bi-concave lens (c) bi-convex lens (d) converging lens
9. A white screen illuminated by red and green light appears (a) red (b) green (c) purple (d) yellow
10. Which of the following instruments makes use of the principle of total internal reflection? (a) sextants (b) periscope (c) microscope (d) telescope
11. The distance between optical centre and twice the principal focus of a lens is called……. (a) Optical centre (b) focal length (c) principal axis (d) radius of curvature
12. A pin 6cm high is placed in frontof a diverging lens of focal length 15cm. calculate the position of the image formed (a) -15cm (b) 15cm  (c) -10cm (d) 10cm 
13. Calculate the power of a converging lens with a focal length of 5cm (a) +0.0D (b) +0.2D(c) -20.0 (d) -0.2D
14. An object is placed 20cm from a converging lens. If the real image formed is 80cm. Find the focal length of the lens? (a)15cm    (b) 30cm (c) 10cm    (d) 16cm
15. Inability of the eye to focus near objects is known as: (a) astigmatism (b) hypermetropia (c) myopia (d) presbyopia 
16. An object placed 15cm from a converging lens from a real image whose magnification is 2.0. What is the focal length of the lens? (a) 10.0cm (b) 6.00cm (c) 5.00cm (d) 1.50cm
17. A converging lens produces an image four times as large as an object placed 25cm from the lens. Calculate its focal length  (a) 100cm (b) 33cm (c) 29cm (d) 20cm
18. A convex lens of focal length 15cm forms a real image 45cm from the lens. Find the magnification of the image (a) 1 (b) 2 (c) 3 (d) 4 
19. For correcting long sight defects in the human eyes, we require ……….. (a) Converging lens (b) diverging lens (c) microscope (d) periscope
20. A magnified and virtual image of a near object is produced by (a) prism binocular (b) astronomical telescope (c) periscope (d) simple periscope
21. When an astronomical telescope is in normal adjustment, the focal length of the objective lens is 50cm and that of the eye piece is 5.0cm. What is the distance between the lenses (a) 10.0cm (b) 30.0cm  (c) 45.0cm (d) 55.0cm
22. Which of the following optical instruments does not make use of a lens? (a) projector (b) periscope (c) eye (d) microscope
23. The ability of the eye to focus object at different distances is called …….. (a) Power    (b) accommodations     (c) normal vision  (d) long sight
24. What part of the camera corresponds to the iris of the eye? (a) diaphragm (b) film (c) lens (d) shutter
25. Binocular vision (a) Restricts the field of view (b) Enables a person to see further (c) Enables objects to be seen in relief (d) Enables objects to be seen clearly
26. Which of the following colours of light is most deviated when light passes through a triangular prism? (a) orange (b) green (c) indigo (d) yellow
27. Which of the following pairs of light rays shows the widest separation in the spectrum of white light? (a) green and blue (b) orange and indigo (c) blue and violet (d) red and yellow
28. The direction of a light ray changes as it passes from one medium to another. The phenomenon is called (a) diffraction (b) reflection (c) dispersion (d) refraction
29. The separation of white light into its constituent colour is known as (a) deviation (b)diffraction   (c) dispersion   (d) deflection
30. Another name for light of one wavelength or colour (a) dispersed light (b) hight light (c) monochromatic light (d) transparent light
31. The following colours are primary colours except? (a)red (b) green (c)blue  (d) yellow
32. When white light passes through a triangular prism, there is dispersion because of (a) diffraction of light (b) polarization of light (c) the difference in speed of the components of light(d) the interference of light waves in glass
33. The frequency of a stretched string has a fundamental note produced given by the relation: (a) f0=V2lTM(b) f0=TM 

(c) f0=V2l(d) f0=M2lTM

1. A boy standing some distance from the foot of a tall cliff claps his hands and hears an echo 0.5s later. If the speed of sound in air is 340m/s, how far is he from the cliff? (a) 17m (b) 24m (c) 85m (d) 170m
2. Sound wave differs from water wave………(a) energy transfer is involve (b) they can be refracted and reflected (c) no transfer of the medium is involved (d)They are longitudinal wave
3. The periodic rise and fall in amplitude or loudness of the sound produced when two notes of nearly equal frequencies are sounded together is called (a) loudness (b) pitch (c) beat (d) note
4. The characteristics note which helps to identify sound from different musical instruments is called (a) quality (b) loudness (c) beat (d) overtones
5. A noise of frequency 2000Hz has a velocity of 400m/s. What is the wavelength of the noise? (a) 0.02m (b) 0.25m (c) 0.2m (d) 2m 
6. A man stands 50m in front of a cliff and claps his hands and the echo is heard 0.3seconds later. Calculate the speed of sound in air in metre per seconds (a) 333 (b) 330 (c) 233 (d) 220
7. A source of sound produces waves in air if wavelength 1.65m. If the speed of sound in air is 330m/s, the period of vibration is (a) 200    (b) 0.005 (c) 0.5 (D) 0.02
8. The speed of sound traveling in various media increases in the following correct order (a) iron bar, air, water    (b) air, iron bar, water  (c) air, water, iron bar (d) water, iron bar, air
9. In stringed instruments like a guitar or violin, high pitched notes are produced by strings that are (a) thick and short (b) thin and short (c) thick and long (d) thin and long
10. Calculate the frequency of fundamental of a closed pipe of length 20cm, if the speed of sound waves in air is 340 m/s (a) 40Hz (b) 200Hz (c) 350Hz (d) 425Hz
11. A tuning fork sounds louder when its stem is pressed against a table top than when held in air because (a) a larger mass of air is set vibrating by the table top (b) the whole table vibrates in resonance (c) the whole table has acquire a larger frequency (d) the fork and the table have the same frequency
12. What type of motion does the skin of a talking drum perform when it is being struck with drumstick? (a) random (b) rotational (c) vibratory (d) translational
13. Calculate the wavelength of a note which is one octave lower than a note of 256 Hz in a medium in which the speed of sound is 352m/s (a) 0.69m (b) 1.38m (c) 2.75m (d) 5.50m

SECTION B

INSTRUCTION: Attempt any five questions from this section. Each question carries 2 marks

1. State Snell’s laws of refraction of light
2. Draw the ray diagram of an object placed (i) at F for a converging lens
3. What is meant by the statement that “the focal length if a converging lens is 20cm”
4. A stone of mass 2.0kg is thrown vertically upwards with a velocity of 20.0m/s, calculate the initial kinetic energy
5. State the newton’s second law of motion
6. Mention two applications of projectiles
7. Two forces A and B acts at 600 to each other. Calculate the resultant force R in terms of A and B
8. Weights 20N and 60N are hung on the points 0.1m and 1.3m respectively on a light beam of length 1.5m. If the balance point is at 1.0m, find the moment of the forces about the balanced point
9. Define these terms as applicable in simple harmonic motion: (i) amplitude (ii) period
10. Define specific heat capacity and give the S.I unit? 

SECTION C

INSTRUCTION: Attempt any three questions from this section.

1. (a) A ray experiences minimum deviation 400 when passing symmetrically through an equilateral glass prism. Calculate the angle of incidence of the ray (refractive index of glass = 1.5)                        5marks

(b) Describe with the aid of a well labeled diagram how a pure spectrum of white light can be produced?                        3marks

(c) Give two conditions necessary for total internal reflection to occur 2marks

1. (a) Explain the following terms: (i) echo (ii) reverberation (iii) resonance                                                    6marsks

(b) An underwater swimmer is at a depth of 12cm below the surface of water. A bird is at a height of 18cm from the surface of water, directly above his eyes. For the swimmer, the bird appears to be at a distance X from the surface of the water. What is the value of X if the refractive index of water is 4/3          4 marks

1. (a) A convex lens placed 8cm from an object forms a virtual image 24cm from the lens. What is: (i) the focal length of the lens (ii) the distance between the object and the lens for which a real image is form            6marks

(b) Distinguish between noise and musical note            2marks

(c) A sound frequency 100Hz and wavelength 3.34m is travelling through air, calculate the velocity of sound in air                    2marks

1. (a) A ship approaches a cliff, its siren is sounded again and the echo is heard in the ship after 12 seconds, 2.1 minutes later the siren was sounded again and the echo was heard 8 seconds later. If the speed of sound in air is 340m/s, calculate the velocity at which the ship was approaching the cliff        5marks

(b) List three classes of musical instruments giving one example in each                                                    3marks

(c) Show by a ray diagram how a right-angled glass prism may be used to invert an erect object                                2marks

1. (a) Distinguish between a real and a virtual image and draw ray diagrams to illustrate how a converging lens can be used to produce each type of image                                                3marks

(b) An object placed at a distance u from a converging lens produces a virtual image 33cm from the object. If the magnification is 4, calculate the: (i) value of u (ii) focal length of the lens (iii) power of the lens            7marks