The energy carried by the incident light is

where h is the Planck constant and f is the frequency of the light. The threshold frequency is the frequency that corresponds to the minimum energy needed to eject the electrons from the metal, so if we substitute the threshold frequency in the formula, we get the minimum energy the light must have to eject the electrons:
Hi there!
We can use the rotational equivalent of Newton's Second Law:

Στ = Net Torque (Nm)
I = Moment of inertia (kgm²)
α = Angular acceleration (rad/sec²)
We can plug in the given values to solve.

Australia separated from other continents and species there evolved independently
Science is open to change because scientists agree that there are no absolute truths, only the best explanations for the data
there are specifically two cases when science can change: -new data is discovered (for example new skeleton makes us revise the known history of homo species)
-a new model is proposed that fits the data better (such as the heliocentric model of Copernicus)
Is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. Two types of electric charges are positive and negative.