
The figure below is a schematic diagram of a reflecting telescope to view distant stars and constellations. is the imaginary axis of the eyepiece and light rays from the distant stars falling in parallel with . The angle between the incident and reflected rays on the objective mirror is and that on the secondary mirror is .

The angle subtended by light rays at the eyepiece is



Important Questions on Lines and Angles
The figure below is a dish antenna which has signal receiver placed at the focus, . The centre of curvature of the antenna is , and is the point on the antenna on the same line joining and . The incoming signals after reflection (The angle of incidence is equal to the angle of reflection), passes through F, where signal receive is placed.
A signal travelling parallel to axis, makes an angle of incidence .
The measure of is _____

Two mirrors and are kept an angle with each other. A ray of light falling on in parallel to suffers reflection at and then at .
The angle of reflection at mirror (marked in the figure) is _____

Rohan made a shape using matchsticks as shown below, by attaching two legs at the opposite vertices of the square. The angle made by each leg with respect to side of the square is . Now Rohan wants to turn the matchstick on the right side so that it is parallel to the one on the left side.
The angle by which Rohan should turn the matchstick on the right side is _____ .

The figure below shows front view of a solar panel fixed on a support, one end of which is firmly grounded at angle of and other end is joined with solar panel using a rotatable hinge. The solar panel is fully raised by rotating by the required angle about the hinge on the support so that light rays falls perpendicular on the panel, at a time when sun is vertical with the ground.
The measure of angle between the support and solar panel once it is fully raised is _____

Sita cutout three triangles of different types from a parallelogram for the purpose of classifying them. is an isosceles triangle, is an obtuse triangle, is an acute triangle. Measure of two angles are marked in the figure.
The measure of angle is _____

In the figure below is meeting junction of three straight roads, . A car upon reaching junction , the car turned right and entered into road .
By what angle did the car turn at junction ?

Below is the picture of Incheon Bridge, New Songdo City, South Korea, designed using cables. The angles between the vertical pole with each cable are equal . The sum of angles each cable making with road is
What is the angle that the cable is making with the road, ?

The picture below is a road around a park, where the roads . and
A person entering into road from road . By what angle should the person turn at ?
