Identify, with the letter X, the position of the focus of the primary mirror.

The diagram shows an incomplete ray diagram which consists of a red ray of light and a blue ray of light which are incident on a converging glass lens. In this glass lens the refractive index for blue light is greater than the refractive index for red light.

Using the diagram, outline the phenomenon of chromatic aberration.

determine the focal length of the lens.

Light passing through this lens is subject to chromatic aberration. Discuss the effect that chromatic aberration has on the image formed on the screen.

calculate the linear magnification.

On the diagram, sketch the part of wavefront X that is inside the lens.

A system consisting of a converging lens of focal length F₁ (lens 1) and a diverging lens (lens 2) are used to obtain the image of an object as shown on the scaled diagram. The focal length of lens 1 (F₁) is 30 cm.

Determine, using the ray diagram, the focal length of the diverging lens.

Hence state how the defect of the converging lens in (a) may be corrected.

The screen is removed and the image is used as the object for a second diverging lens B, to form a final image. Lens B has a focal length of $2.00 \mathrm{cm}$ and the final real image is $8.00 \mathrm{cm}$ from the lens. Calculate the distance between lens A and lens B.

Calculate the distance between the lenses.

The distance between the lenses is 18 cm. Determine the focal length of L₂.

Determine, by calculation, the linear magnification produced in the above diagram.

Show that the image of the object formed by L₁ is 12 cm to the right of L₁.

On the diagram draw rays to locate the focal point of L₂. Label this point F.

Explain your sketch in (a)(i).

Determine the distance between the lamp and the lens.

State what is meant by a virtual image.

Suggest how the refracted rays in (a) are modified when the converging lens is replaced by a diverging lens.

Determine the position of the image.

The incident ray shown in the diagram makes a significant angle with the optical axis.

(i) State the aberration produced by these kind of rays.

(ii) Outline how this aberration is overcome.

Construct a ray diagram in order to locate the position of the image formed by the mirror. Label the image $\text{I}$.

Estimate the linear magnification of the image.

Explain chromatic aberration, with reference to your diagram in (b)(i).

Calculate, in cm, the distance between the eyepiece and the image formed by the objective lens.

Calculate the focal length of the lens.

Draw on the diagram the three wavefronts after they have passed through the lens.

Calculate the total magnification of the object by the lens combination.

Lens A has a focal length of $4.00 \mathrm{cm}$. An object is placed $4.50 \mathrm{cm}$ to the left of A. Show by calculation that a screen should be placed about $0.4 \mathrm{m}$ from A to display a focused image.

On the diagram, sketch the wavefront in air that passes through point P. Label this wavefront Y.

Two parallel rays are incident on a system consisting of a diverging lens of focal length 4.0 cm and a converging lens of focal length 12 cm.

The rays emerge parallel from the converging lens. Determine the distance between the two lenses.

Identify whether the image is real or virtual.