Which element is used in safety flares and fireworks because it burns so brightly?
a. Potassium
b. Magnesium
c. Carbon
d. Chlorine
b
You might also like to view...
Stars A and B have the same temperature, but star A has twice the radius of star B. What is the ratio of star A’s power output to star B’s output due to electromagnetic radiation? The emissivity of both stars can be assumed to be 1
1.4 2.8 3.16 4.64
Optics of the Eye: A person's near point is 25 cm, and her eye lens is 2.7 cm away from the retina. What must be the focal length of this lens for an object at the near point of the eye to focus on the retina?
A. -3.4 cm B. -2.4 cm C. 2.4 cm D. 3.4 cm E. 2.6 cm
A small car pushes on a disabled truck, accelerating it slowly forward. Each exerts a force on the other as a result of their contact interaction. Which vehicle exerts the greater force on the other?
A. The car B. The truck C. Both forces have the same magnitude. D. The truck doesn’t exert any force on the car. E. One needs more information to answer.
How much energy would be required to accelerate a 77. kg professor from rest to 90% the speed of light?
A) 2.3 mc2 B) 0.30 m c2 C) 1.3 m c2 D) 0.41 m c2 E) 0.50 m c2