If light travels at 3 · 108 m/s and its frequency is 6 · 1015 hz, then its wavelength is: a) 10 · 107 m b) 5 · 10-8 m c) 5 · 10-7 m d) 10 · 10-7 m

 5*10^-8 (B)

Explanation:  

-Given that the light is the speed

-We will be following the formula :

V= f (λ)

Where,  

V is the velocity  

F is the frequency  

λ is the wavelength  

3*10^8 = (6*10^15 )* λ

(3*10^8)/ (6*10^15 ) =  λ

5*10^-8m = λ answer

Note: λ is initially 0.5*10^-7 but to make it in the standard form it should be 5*10^-8. And do not forget to place the unit for the wavelength i.e. meter(m) otherwise you may lose marks!

i don't understand is there any other way you can rephrase it plz let me know in the comments and i will do it.

explanation:

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft