A convex mirror makes a reflected light rays spread out.
        
                    
             
        
        
        
Assume no air resistance, and g = 9.8 m/s².
Let
x =  angle that the initial velocity makes with the horizontal.
u = 30 cos(x), horizontal velocity
v = 30 sin(x), vertical launch velocity
The horizontal distance traveled is 55 m, therefore the time of flight is
t = 55/[30 cos(x)] = 1.8333 sec(x)  s
With regard to the vertical velocity, and the time of flight,obtain
[30 sin(x)]*(1.8333 sec(x)) + (1/2)*(-9.8)*(1.8333 sec(x))² = 0
 55 tan(x) - 16.469 sec²x = 0
55 tan(x) - 16.469[1 + tan²x] = 0
16.469 tan²x - 55 tan(x) + 16.469 = 0
tan²x - 3.3396 tan(x) + 1 = 0
Solve with the quadratic formula.
tan(x) = 0.5[3.3396 +/- √(7.153)] = 3.007 or 0.3326
Therefore
x = 71.6° or x = 18.4°
The time of flight is
t = 1.8333 sec(x) = 5.8096 s or 1.932 s
The initial vertical velocity is
v = 30 sin(x) = 28.467 m/s or 9.468 m/s
The horizontal velocity is
u = 30 cos(x) = 9.467 m/s or 28.469 m/s
If t = 5.8096 s,
  u*t = 9.467*5.8096 = 55 m (Correct)
or
 u*t = 28.469*15.8096 = 165.4 m (Incorrect)
Therefore, reject x = 18.4°. The correct solution is
t = 5.8096 s
x = 71.6°
u = 9.467 m/s
v = 28.467 m/s
The height from which the ball was thrown is
h = 28.467*5.8096 - 0.5*9.8*5.8096² = -110.4 m
The ball was thrown from a height of 110.4 m
Answer: h = 110.4 m
        
             
        
        
        
It's Photoelectric Effect, I just a test with this same question. I am not good for explaining exactly how, but I was right.
        
                    
             
        
        
        
Option 4 ( R2 and R3 ) is the correct answer.
Explanation:
- In the below given diagram, we can see a circuit diagram that has four resistors such as R1, R2, R3, and R4.
- The opening of the circuit is noted as "a" and the ending is noted as "b".
- By observing the above diagram, we can clearly see that R2 and R3 are the pair of resistors that are connected in a parallel manner.
- Where all the other resistors such as R1 and R4 are neither connected in parallel nor in series.
Hence we can conclude that Resistor R2 and R3 are the ones that are connected in parallel.