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:
Answer:
A. The bird watcher followed the south trail a distance of five kilometers in 45 minutes.
Answer:
the coefficient of volume expansion of the glass is 
Explanation:
Given that:
Initial volume of the glass flask = 1000 cm³ = 10⁻³ m³
temperature of the glass flask and mercury= 1.00° C
After heat is applied ; the final temperature = 52.00° C
Temperature change ΔT = 52.00° C - 1.00° C = 51.00° C
Volume of the mercury overflow = 8.50 cm^3 = 8.50 × 10⁻⁶ m³
the coefficient of volume expansion of mercury is 1.80 × 10⁻⁴ / K
The increase in the volume of the mercury = 10⁻³ m³ × 51.00 × 1.80 × 10⁻⁴
The increase in the volume of the mercury = 
Increase in volume of the glass = 10⁻³ × 51.00 × 
Now; the mercury overflow = Increase in volume of the mercury - increase in the volume of the flask
the mercury overflow = 






Thus; the coefficient of volume expansion of the glass is 
The solution is 'supersaturated' ... holding more solute than it's supposed to be able to hold.
Answer:
Velocity is the rate of change of displacement.