Answer:
3. both are true.
Explanation:
Energy increses with decrease in wavelenght.
For photoemission to occur, a threshold energy barrier must be broken.
Higher energy means more electrons will be emmited.
The electrons emmited will posses energy that is less than the incident energy by the value of the threshold energy.
So the higher the energy, the higher the energy possessed by the electrons.
Answer:
Convex lens and convex mirrors are similar that
1. They have the same image characteristics at various object positions
2. They possess a positive focal length
3. Both their ray lines converge to a particular focal point
To solve this problem it is necessary to apply the law of Malus which describes the change in the Intensity of Light when it crosses a polarized surface.
Mathematically the expression is given as

Where,
= Initial Intensity
I = Final Intensity after pass through the polarizer
= Angle between the polarizer and the light
Since it is sought to reduce the intensity by half the relationship between the two intensities will be given as

Using the Malus Law we have,





Angle with respect to maximum is 
Answer:
Explanation:
distance of fan A = 18.3 m
distance of fan B = 127 m
speed of sound (s) = 343 m/s
What is the time difference between hearing the sound at the two locations?
time (T) = distance / speed
- time for sound to reach fan A = 18.3 / 343 = 0.053 s
- time it takes for sound to reach fan B = 127 / 343 = 0.370 s
- time difference = 0.370 - 0.053 = 0.317 s