Answer:
sorry but I can understand the question
Answer:
Explanation:

from steam tables , at 250 kPa, and at
T₁ = 80⁰C ⇒ h₁ = 335.02 kJ/kg
T₂ = 20⁰C⇒ h₂ = 83.915 kJ/kg
T₃ = 42⁰C ⇒ h₃ = 175.90 kJ/kg
we know


according to energy balance equation


Answer:

Explanation:
The definition of the intensity in terms of power is given by:

Where:
- P is the power
- A is the area
If the sound emits uniformly in all directions and that there are no reflections, we can assume the geometry of the wave sound is spherical.
Let's recall the area of a sphere is 
To the first location we have:

and to the second location we have:

Now, we can divide each intensity to find the second intensity.




I hope it helps you!
Answer:
1.11 V
Explanation:
Given that the Einstein photoelectric equation states that;
KE = E - Wo
E = energy of incident photon
Wo= work function of the metal
E = hf = 6.64 x 10-34 * 6 x 1014
E = 39.84 * 10^-20 J or 3.98 * 10^-19 J
KE = 3.98 * 10^-19 J - 2.2 x 10-19J
KE = 1.78 * 10^-19J
We convert this value of KE to electron volts
KE = 1.78 * 10^-19J/1.6 x 10-19C
KE = 1.11 eV
Hence; 1.11 V will be just sufficient to stop electrons emitted by the sodium photo-plate reaching the collector plate.
I believe your answer would be A. Due to the friction of pushing the chair while it’s on the floor