1 pc

A red light beam is shining on a piece of cesium that is connected in a

photoelectric circuit. What should be added to the circuit to determine

whether red light produces photoelectrons? *

A voltmeter

An ammeter

A battery

A spectroscope

A spectroscope

Explanation:

A spectroscope is used by scientists to separate a source of light ( usually white light ) into its various compositions. i.e it is used to determine the chemical makeup of a visible source of light. hence to determine whether the red light produces photo electrons, which is a chemical makeup of visible light a spectroscope should be added to the circuit.

photo electrons are electrons emitted/ejected from a surface usually metallic surface in the form of a photoelectric effect  when a source of light is shines on the surface

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.