Lenses (physics Only) (GCSE Physics)

A lens has power P measured in dioptres such that P = 1/f (f in metres). What is the power of a lens with focal length 0.25 m?

A beam of red light and a beam of blue light enter a glass prism at the same angle. Which statement is true about their angles of refraction in the glass?

Which statement about virtual images formed by lenses is correct?

When light passes from glass (n = 1.5) to air, total internal reflection can occur. Which condition must be true for total internal reflection to be possible?

A lens produces an image with magnification m = -2. What does this tell you about the image?

A student measures the focal length of a converging lens by focusing parallel sunlight to a point on a screen and measuring the distance from lens to screen. Which property makes this method accurate?

Light slows when entering glass from air. Which of the following explains why the wavelength changes but frequency remains the same?

An object 2.0 cm tall is placed 15 cm in front of a converging lens that produces an image 30 cm on the other side. What is the image height?

A student uses the thin lens equation and obtains 1/f = 1/(-20 cm) + 1/(40 cm) and finds f = -40 cm. What type of lens and image does the negative focal length indicate?

A monochromatic light beam strikes a glass–air boundary from inside the glass. The critical angle for the glass–air interface is 42°. If the angle of incidence inside the glass is 50°, what happens?

A ray of light travelling from air (n ˜ 1.00) into glass with refractive index 1.50 strikes the surface at 30° to the normal. Using Snell’s law, which is closest to the angle of refraction in the glass?