The kilogram is the Standard International System of Units unit of mass. It is defined as the mass of a particular international prototype made of platinum-iridium and kept at the International Bureau of Weights and Measures.
The efficiency of the engine at the given useful energy and input energy is 28%.
The given parameters:
- <em>Input energy of the engine, = 125 J</em>
- <em>Useful energy of the engine, 35 J</em>
The efficiency of the engine is defined as the ratio of the output energy (useful energy) to the input energy and it is calculated as follows;

Thus, the efficiency of the engine at the given useful energy and input energy is 28%.
Learn more about efficiency of engine here: brainly.com/question/6751595
Answer:
The value is
Explanation:
From the question we are told that
The wavelength is 
The velocity is 
The mass of electron is 
Generally the energy of the incident light is mathematically represented as

Here c is the speed of light with value
h is the Planck constant with value 
So

=> 
Generally the kinetic energy is mathematically represented as

=> 
=> 
Generally the ionization energy is mathematically represented as

=>