What is the unit of magnification?

Correct option is D

• The correct answer is (D) It has no unit.
• The unit of magnification is none of the above, it has no unit: 
• Explanation: Magnification is the ratio of two lengths, so it has no units. It is the ratio of the size of an image to the size of an object, or the ratio of the image distance to the object distance.
• Units for image and object height: The image height and object height should both be measured in the same units, such as centimeters (cm) or millimeters (mm).

Incorrect options explanation:

• Dioptre: The optical power of a lens or curved mirror is measured in units of 1 dioptre, which is equal to the reciprocal of the focal length (f ). In metres, the focal length is expressed. The dioptre, which has a focal length of one metre and is represented by the symbol (D), is the SI unit of lens power.
• Newton: ​In the International System of Units (SI units), the letter N stands for newton, an absolute measure of force. It is described as the amount of force required to accelerate a mass of one kilogramme by one metre per second. Newton was given its name in honour of Sir Isaac Newton, whose second rule of motion defines the modifications that a force might make to a body's motion.
• Centimeter: Centimeters, which are metric units of measurement, are used to determine an object's length.The abbreviation is cm. 100 centimetres make to a metre. The unit of measure changes to cm2 when determining an object's surface area. The measurement unit changes to cm3 for determining an object's volume.