Lenses

Some people wear glasses when they are reading.

Figure 6 shows parallel rays of light passing through a convex lens from a pair of reading glasses.

What name is given to point X in Figure 6 ?

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Light changes direction as it enters the lens.

What is the name of this process?

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Which of the following is the shape of a convex lens?

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Figure 7 shows a lens forming a magnified image of an object.

Measure the image height and the object height in Figure 7.

Calculate the magnification produced by the lens.

Use your answers to Question 05.4 and the equation:

Why does magnification have no unit?

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Some reading glasses contain lenses made from blue glass.

The blue glass acts as a filter.

Describe what happens to white light incident on colourless glass and white light incident on blue glass.

Telescopes are used to look at distant objects.

Some telescopes use lenses to form an image.

Figure 5 shows two parallel rays of light incident on a lens in a telescope.

The principal focus of the lens is labelled F.

What type of lens is shown in Figure 5 ?

Complete the ray diagram in Figure 5.

The James Webb Space Telescope can detect electromagnetic radiation beyond the visible spectrum.

The shortest wavelength of electromagnetic radiation that can be detected by the James Webb Space Telescope is 0.60 m.

speed of electromagnetic radiation = 3.0 × 10⁸ m/s

Calculate the frequency of electromagnetic radiation that has a wavelength of

Use the Physics Equations Sheet.

Complete the sentence.

Electromagnetic radiation detected from distant galaxies is red-shifted.

This means that the electromagnetic radiation shows an increase in

Why is the electromagnetic radiation from distant galaxies red-shifted?

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The James Webb Space Telescope has detected electromagnetic radiation from many different galaxies.

Electromagnetic radiation from one of the galaxies detected shows the greatest red-shift ever observed.

What conclusion can be made about the distance to this galaxy?

The James Webb Space Telescope is an artificial satellite that orbits the Sun at a constant speed.

Explain why the velocity of the satellite changes as it orbits the Sun.

Lenses can be used to form an image of an object.

Figure 20 shows parallel rays of light being refracted by a convex lens.

What is the position marked ‘ F ’ called? Tick (✓) one box.

Complete the ray diagram in Figure 21 to show how a concave lens forms the image of the object. Use an arrow to represent the image.

Figure 22 shows how a convex lens can be used to form a magnified image of an object.

Give two ways that the image formed by the convex lens in Figure 22 is similar to the image formed by the concave lens.

A convex lens is used as a magnifying glass to identify a symbol on the back of a silver spoon. The symbol has an actual height of 1.6 mm. The magnification produced by the lens is 3.5 Calculate the image height of the symbol when viewed through the magnifying glass. Use the Physics Equations Sheet.

Figure 14 shows how a lens forms an image of an object.

What type of lens is represented in Figure 14 ? Tick (✓) one box.

Measure the image height and the object height in Figure 14.

Calculate the magnification produced by the lens. Use the equation:

Which two words describe the image in Figure 14 ? Tick (✓) two boxes.

The object was blue. A student looked at the blue object through a green filter. Complete the sentences. Choose answers from the box.

black blue green red white

Looking at the blue object through a green filter makes the object appear

Lenses are used to form images of objects.

Figure 6 shows how a concave lens forms an image of an object.

The image of the object in Figure 6 is upright. Give two other words that describe the image.

Figure 7 shows an object near to a convex lens. Complete the ray diagram to show how the image is formed. Use an arrow to represent the image.

The position of an image formed by a convex lens varies with the distance between the object and the lens. Figure 8 shows the results of a student’s investigation using a convex lens.

Describe how the distance of the image from the lens decreases as the distance between the object and the lens increases.

The student measured the distance from the image to the lens four times. The distance between the object and the lens did not change. The 4 measurements from the image to the lens were: 1.9 cm 1.7 cm 2.2 cm 1.4 cm Calculate the uncertainty in the measurements.

Figure 9 shows a spotlight containing a convex lens. A red filter is placed in front of the spotlight. The spotlight is directed at a blue object.

Explain why the blue object appears black.

A door is fitted with a security lens and a lock. The security lens allows a person to see a visitor before opening the door. The security lens is concave.

Figure 5 is an incomplete ray diagram representing a visitor standing near the security lens. Complete Figure 5 to show how an image of the visitor is formed by the concave lens. Draw an arrow to represent the image.

The visitor moves further away from the security lens in the door. How does the size of the image change? Tick (✓) one box.

Figure 6 shows a diagram of the lock. The door unlocks when the switch is closed.

Which material should the bolt be made from? Tick (✓) one box.

Explain why the door unlocks when the switch is closed.

When the door unlocks, a force of 2.88 N is applied to the spring. The spring extends by 1.50 cm. Calculate the spring constant of the spring.

Give two ways the resultant force on the bolt could be increased.

Figure 20 shows parallel rays of light being refracted by a convex lens.

What is distance ‘ X ’ called?

Lenses can be used to form the image of an object. Complete the ray diagram in Figure 21 to show how a convex lens forms the image of the object. Use an arrow to represent the image.

Figure 21

Figure 22 shows how a concave lens forms the image of an object.

Give one similarity and one difference between the image formed by the convex lens and the image formed by the concave lens.

A person uses a lens to read the letters on the back of a coin. The image height of the letters on the coin is 9.0 mm The magnification produced by the lens is 6.0

Calculate the height of the letters on the coin. Use the Physics Equations sheet.

Figure 1 shows parallel rays of light being refracted by a convex lens.

What is distance ‘ X ’ called?

Lenses can be used to form the image of an object. Complete the ray diagram in Figure 2 to show how a convex lens forms the image of the object. Use an arrow to represent the image.

Figure 2

Figure 3 shows how a concave lens forms the image of an object.

Give one similarity and one difference between the image formed by the convex lens and the image formed by the concave lens.

A person uses a lens to read the letters on the back of a coin. The image height of the letters on the coin is 9.0 mm The magnification produced by the lens is 6.0

Calculate the height of the letters on the coin. Use the Physics Equations sheet.

Figure 1 shows how a concave lens forms an image of an object.

Which point on Figure 1 marks the position of the principal focus of the lens? Tick one box.

Which two words describe the image? Tick two boxes.

Calculate the magnification produced by the lens. Use the equation:

Complete the sentence. Choose an answer from the box.

decrease increase not change

As the object is moved further away from the lens, the size of