Answer:
The value is 
Explanation:
From the question we are told that
The power rating of the bulb is 
The frequency is 
The percentage of the input power that is emitted as visible light is 
Generally the amount of power emitted as visible light is mathematically represented as

=> 
=> 
Generally the amount of energy emitted as light is mathematically represented as

Here n is the number of photon , h is the Planks constant with value 
Generally this power emitted as visible light is mathematically represented as

=> 
=> 
=> 
=> 