Compound Microscope: A compound microscope has a 18-cm-long barrel and an objective lens with a focal length of 8.0 mm. What is the focal length of the eyepiece to give a total magnification of 240? It is adjusted for minimum eyestrain for persons with a near point of 25 cm.

A. 1.3 m
B. 1.5 cm
C. 1.9 cm
D. 2.1 cm
E. 2.3 cm


Answer: D

Physics & Space Science

You might also like to view...

What is the symbol used on the periodic table for the element Rubidium?

a. Rf b. Hs c. Rb d. No e. U

Physics & Space Science

The moons of Mars, Phobos (Fear) and Deimos (Terror), are very close to the planet compared to Earth's Moon. Their orbital radii are 9,378 km and 23,459 km respectively. What is the ratio of the period of revolution of Phobos to that of Deimos?

A) 0.2528 B) 0.3998 C) 1.582 D) 2.858 E) 3.956

Physics & Space Science

The brightest object in the sky is

a. the Sun. b. the Moon. c. Venus. d. Mars.

Physics & Space Science

In an x-ray diffraction experiment, using x-rays of wavelength ? = 0.434 × 10^?10 m, a first-order maximum occurred at 8° off the crystal plane. Find the distance d between crystal planes

a. 1.56E–10 m b. 2.19E–11 m c. 4.88E–10 m d. 1.70E–9 m e. 3.12E–10 m

Physics & Space Science