CIE iGCSE Co-Ordinated Science P3.2.3 Thin converging lens Exam Style Questions Paper 3
Question
Fig. 9.1 shows a moth(a) A student forms an image of the moth on a screen using a thin converging lens.
A ray of light has been drawn from each of the moth’s wings to the screen on the ray diagram in Fig. 9.2.
The start of another ray of light has been drawn from the moth’s body
(i) On Fig. 9.2, complete the ray of light from the moth’s body to show where it appears on the screen.
(ii) Draw a double headed arrow (↕) on Fig. 9.2 to show the size and position of the image of the moth on the screen.
(iii) State the name of the point labelled F on Fig. 9.2.
(b) Moths are able to hear the highest frequency of any animal. The greater wax moth can hear frequencies up to 300 000 Hz.
(i) State the maximum audible frequency for a healthy human ear in Hz.
frequency = ……………………………………………. Hz
(ii) State what is meant by the frequency of a wave.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(c) Fig. 9.3 shows an electric insect trap that uses an ultraviolet lamp to attract insects
(i) There is a potential difference (p.d.) of 240 V across the ultraviolet lamp.
There is a current of 0.75 A in the ultraviolet lamp.
Calculate the resistance of the ultraviolet lamp.
resistance = …………………………………………….. Ω
(ii) State one danger of ultraviolet radiation to humans.
…………………………………………………………………………………………………………………….
▶️Answer/Explanation
Ans :
9(a)(i) horizontal ray continued to lens axis ;
diagonal straight line from lens through F to screen ;
9(a)(ii) position of image correctly indicated ;
9(a)(iii) principal focus / focal point ;
9(b)(i) 20 000 (Hz) ;
9(b)(ii) number of waves that pass a fixed point per unit time / owtte ;
9(c)(i) evidence of resistance = potential difference ÷ current / 240 ÷ 0.75 ;
320 (Ω) ;
9(c)(ii) skin cancer / cataracts and eye damage / immune system depression / premature aging and other skin damage ;
Question
A person climbs a mountain.
(a) The person is exposed to infrared and ultraviolet radiation from the Sun.
Infrared and ultraviolet radiation are part of the electromagnetic spectrum.
(i) Fig. 3.1 shows an incomplete electromagnetic spectrum.
On Fig. 3.1, write infrared and ultraviolet in their correct places.
(ii) Ultraviolet waves travel at 300 000 000 m / s in a vacuum.
State the speed of infrared waves in a vacuum.
(b) The person makes a loud sound and then hears an echo.
State what is meant by an echo.
(c) The person takes a photograph with a camera.
The camera contains a thin converging lens.
Fig. 3.2 shows an incomplete ray diagram for a thin converging lens forming an image.
(i) State the name of the points labelled F on Fig. 3.2.
(ii) On Fig. 3.2:
• draw a line to complete the path of ray 2
• draw the image formed
• label the image.
(d) The person drops the camera from the top of the mountain. The camera falls down the mountain.
Fig. 3.3 shows the distance–time graph for the motion of the camera over the first 6.0 s
Use Fig. 3.3 to determine the average speed of the camera over 6.0 s.
▶️Answer/Explanation
Ans : 3(a)(i)
infrared correct ;
ultraviolet correct ;
3(a)(ii) 300 000 000 (m / s) ;
3(b) the reflection of sound ;
3(c)(i) principal focus / focal point ;
3(c)(ii) horizontal line drawn from lens to intersect with ray 1 ;
inverted (labelled) arrow for image ;
3(d) total distance 180m ;
evidence of speed = distance ÷ time / 180 ÷ 6.0 ;
30 (m/ s) ;
Question
(a) Fig. 6.1 shows an athlete running on a level road.
Four forces A, B, C and D act on the runner.
Force B is the driving force which moves the athlete forward.
State the names of forces C and D.
C …………………………………………………………………………
D …………………………………………………………………………
(b) Complete the sentence to describe how forces change a body.
Forces may change the direction of motion of a body,
the …………………………………………………………………. of a body
and the …………………………………………………………………. of a body.
(c) The athlete runs up a hill at constant speed.
Use words or phrases from the list below to complete the sentences about the energy transfers taking place. Each word or phrase may be used once, more than once or not at all.
chemical potential gravitational potential
kinetic light
Stored …………………………………………………… energy from food is
transferred to …………………………………………………… energy as the athlete moves.
As the athlete moves up the hill his store of …………………………………………………… energy increases.
The speed of the athlete is constant when moving up the hill, so his …………………………………………………… energy remains constant.
(d) Explain why the athlete’s power output is greater when he runs faster.
(e) A photographer takes a photograph of the athlete using a digital camera with a thin converging lens as shown in Fig. 6.2.
Two rays of light are shown passing from the head of the athlete to the lens.
(i) A focused image of the athlete’s head is formed on the image sensor.
Complete Fig. 6.2 to show how these two rays pass from the lens to form the image on the sensor.
(ii) On Fig. 6.2, draw a double headed arrow (↔) to show the focal length of the lens.
(iii) Circle two words or phrases that describe the image formed.
diminished enlarged inverted
same size upright
▶️Answer/Explanation
Ans : 6(a) C weight ;
D drag / air resistance ;
6(b) Any two from size ;
shape ;
speed ;
6(c) chemical potential kinetic gravitational potential kinetic;
6(d) rate of work done increases;
6(e)(i) ray 1 refracts through F and meets ray 2 on the image sensor ;
ray 2 continues in a straight line onto image sensor ;
6(e)(ii) focal length correctly shown ;
6(e)(iii) inverted ;
diminished ;
Question
(a) Fig. 9.1 shows a rocket about to be launched.
(i) The weight of the rocket is 8000000N.
When the rocket is launched, the upward force exerted by the rocket is 12000000N.
Calculate the resultant upward force on the rocket.
resultant force = …………………………………………….. N
(ii) Explain why the resultant force cannot be zero, when the rocket is launched.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(iii) The rocket travels 385000km from the Earth to the Moon in 75 hours.
Calculate the average speed of the rocket in km/ s.
speed = ………………………………………… km/s
(b) An astronaut on the rocket uses a telescope to view a star.
Fig. 9.2 shows a lens that is used in the telescope. Light rays from the star pass through the
lens and are focused at the principal focus.
(i) On Fig. 9.2, label the principal focus of the lens with the letter F.
(ii) On Fig. 9.2, draw a double headed arrow ( ↔ ) to indicate the focal length of the lens.
(iii) State the name of the process that occurs when light passes into the lens and the direction of the light changes.
…………………………………………………………………………………………………………………….
(c) The astronaut communicates with Earth using radio waves.
(i) Place radio waves in the correct place in the incomplete electromagnetic spectrum shown in Fig. 9.3.
Fig. 9.3
(ii) State which part of the electromagnetic spectrum has the greatest frequency.
…………………………………………………………………………………………………………………….
(iii) Explain why it is not possible for the astronaut to use sound waves to communicate directly with Earth.
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
▶️Answer/Explanation
Ans: 9(a)(i) 4 000 000 (N) ;
9(a)(ii) rocket would not, move/take off ;
9(a)(iii) conversion of 75 hours to seconds / 270 000 s ;
speed = distance ÷ time or substituted distance ÷ time ;
speed = 1.43 (km/s) ;
9(b)(i) principal focus correctly identified ;
9(b)(ii) focal length correctly identified ;
9(b)(iii) refraction ;
9(c)(i)
9(c)(ii) $\gamma$- rays ;
9(c)(iii) there is no medium / there is a vacuum ;
no particles to transfer the vibrations (preventing sound from travelling) ;
Question
(a) A person standing on a warm, sunny beach is exposed to several forms of electromagnetic radiation.
Fig. 12.1 shows part of the electromagnetic spectrum.
Complete Fig. 12.1 by writing the names of the other two forms of electromagnetic radiation in the correct places.
(b) The person stands with both feet on some very soft sand on the beach.
When one foot is lifted off the sand, the other foot sinks deeper into the sand.
Explain why this happens.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
(c) A sample of sand has a mass of 8000kg.
This sand has a density of 1600kg/m$^{3}$.
(i) Calculate the volume of this sample of sand.
volume = …………………………………. m$^{3}$
(ii) Show that the weight of this sample of sand is 80000N.
The gravitational field strength, g, is 10N/kg.
(d) A piece of glass has been left on the beach. The glass acts like a convex lens focusing the Sun’s rays.
Fig. 12.2 shows two rays of light passing through a convex lens.
(i) Complete the light rays in Fig. 12.2 to show how the light rays are focused by the lens.
(ii) State the name of point F.
…………………………………………………………………………………………………………………….
(iii) On Fig. 12.2, draw a double headed arrow (↔) to indicate the focal length of the lens.
▶️Answer/Explanation
Ans: 12(a)
microwaves in correct place ;
X-rays in correct place ;
12(b) area decreases ;
so pressure increases ;
12(c)(i) volume = mass / density (in any form symbols or words) or 8000 / 1600 ;
= 5 (m$^{3}$ ) ;
12(c)(ii) 8000 × 10 ;
(= 80 000 N)
12(d)(i) rays meet at focus (F) ;