X-rays

Microwaves

Radiowaves

Sound waves

Human eye is a refracting system containing a diverging lens.

The retina of the human eye contains millions of light sensitive cells, called rods and cones, which convert the light into electrical messages.

Every image that is focused on the retina is upside down.

We need both eyes to judge the relative positions of objects accurtely.

Ultrasonic waves cannot get reflected, refracted or absorbed.

Ultrasonic waves are used to detect the presence of defects like cracks, porsity, etc. in the internal structure of common structure materials.

ultrasonic waves can be used for making holes in very hard materials like diamond.

Ultrasonic waves cannot travel through vacuum.

The centripetal acceleration of the object is smaller for a gentle curve (i.e. curve of larger radius) than that for a sharp curve (i.e. curve of smaller radius).

The centripetal acceleration is greater for a gentle curve than that for a sharp curve.

The centripetal acceleration is the same for both the gentle and sharp curves.

The centripetal acceleration causes the object to slow down.