B because 2800 divide by 40 is 20
The answer would be B. Magnetic fields are invisible they cannot be directly observed
Answer:
The objective lens is an optical tool used to focus an image.
Explanation:
The objective lens is an optical tool that collects light emitted by an object under observation and focuses the rays of light in order to form a real and magnified image They are used in optical instruments like microscopes, cameras, telescopes, etc. and are also referred as objective or object glasses.
The answer for this question is A
