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.
…………………………………………………………………………………………………………………….