A parallel-plate capacitor in air has circular plates of radius 2.8 cm separated by 1.1 mm. Charge is flowing onto the upper plate and off the lower plate at a rate of 5 A. Find the time rate of change of the electric field between the plates.

The time rate of change of the electric field between the plates is    

Explanation:

From the question we are told that

    The  radius is  

     The distance of separation is  

      The  current is  

Generally the electric field generated is mathematically represented as

Where is the permitivity of free space with a value

So the time rate of change of the electric field between the plates is mathematically represented as

But

So  

substituting values  

the answer would be a

you'd use the equation that establishes a relationship between  energy  and  wavelength, which looks like this

e=h⋅cλ, where

λ  - the wavelength of the photon; c  - the speed of light, usually given as  3⋅108m/s; h  -  planck's constant, equal to  6.626⋅10−34j s

plug the value you were given for the energy of the photon in the above equation to get the wavelength

e=h⋅cλ⇒λ=h⋅ce

λ=6.626⋅10−34js⋅3⋅108ms−1.257⋅10−24j=1.581⋅10−1m