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.
 
        
             
        
        
        
A free-falling object is an object moving under the effect of gravitational forces alone
The correct option to select for the True or False question is False
The reason the above selected option is correct is as follows:
According to Newton's second law of motion, we have;
Force = Mass × Acceleration
The force of gravity is 
Where;

m  = The mass of the object
∴ The force acting on an object in free fall,  = m × g
 = m × g
Therefore the acceleration of an object in free fall is the constant acceleration due to gravity, and it therefore, does not change with time
The correct option for the question, acceleration of a free-falling object in a frictionless environment increases as a function of time is <u>False</u>
<u></u>
Learn more about object in free fall here:
brainly.com/question/13712424
brainly.com/question/11698474
 
        
             
        
        
        
Answer:
t = 13.7 s or t = 14 s with proper significant figures
Explanation:
The initial speed is 0 m/s since the car starts from rest, acceleration is 5.5 m/s2 and distance is 523 m. 
Since we have initial speed, acceleration and distance we can use the following formula to find the time. We can now use algebra to work out our answer.
d = vt +  at²
at² 
523 = (0)t + ( )(5.5)t²
)(5.5)t²
523 = 2.8t²
186.8 = t²
13.7 s = t
(t = 14 s with proper significant figures)