Question

a substance with a high index of refraction will cause light to travel at a relatively faster speed within that substance compared to a substance with a lower index of refraction. false true light travels in a straight line in a uniform medium. false true which of the following regions of the electromagnetic spectrum is used for transmitting radio and television signals? microwaves gamma rays radio waves visible light the image formed by a convex mirror is always smaller than the object.

Explanation:

• For the first statement: The formula for the refractive index \(n=\frac{c}{v}\), where \(c\) is the speed of light in vacuum and \(v\) is the speed of light in the medium. So, \(v = \frac{c}{n}\). A higher \(n\) means a lower \(v\). So the statement "A substance with a high index of refraction will cause light to travel at a relatively faster speed within that substance compared to a substance with a lower index of refraction" is false.
• For the second statement: Light travels in a straight - line in a uniform medium (rectilinear propagation of light). So the statement "Light travels in a straight line in a uniform medium" is true.
• For the third statement: Radio waves are used for transmitting radio and television signals. Microwaves are used in microwave ovens and satellite communication. Gamma rays are used in cancer treatment. Visible light is for vision.
• For the fourth statement: A convex mirror always forms a virtual, upright, and diminished (smaller than the object) image.

Answer:

• First question: A. False
• Second question: B. True
• Third question: C. Radio waves
• Fourth question: B. True