A 12-V DC automobile head lamp is to be used on a fishing boat with a 24-V power system. The head lamp is rated at 50 W. A resistor is to be connected in series with the lamp to permit it to operate on 24 V. What should be the resistance and power rating of the resistor?

The  resistance is  

Explanation:

From the question we are told that

    The  voltage  rating of the headlamp is  

     The  voltage of the power system is  

     The  power rating of the headlamp  is  

Generally the power which the resistor dissipates is mathematically represented as

=>      

=>  

Generally the resistance is

see earlier