i have problem finding Vgs, the answer is 9.09 volts. please help me! if possible please tell me how does the circuit work too. i appreciate any one who can help me! please the the upload photo for the question.

 

The 100R and 1k resistors are a simple voltage divider. So it's 10V over 1100 Ohms and therefore 9.09 over the 1k.

10V input signal, Mosfet turns on.
0V input signal, Mosfet turns off.

 

Thanks a lot for the guide!! i understand already!! But what if it's asked u to calculate the average power delievered to the resistive load????

 

Q1) How much power is being delivered to the load when the MOSFET is on?

Q2) How much energy is delivered to the load during the portion of each cycle that the MOSFET is on?

Q3) How much power is being delivered to the load when the MOSFET is off?

Q4) How much energy is delivered to the load during the portion of each cycle that the MOSFET is off?

Q5) How much energy total is delivered to the load during each cycle?

Q6) What is the average power delivered to the load?

 

Calculate the average current through the load first, (I^2)R will give the avg. power.

 

But what if it's asked u to calculate the average power delievered to the resistive load????

You will have to examine the given information to find the voltage across the load when "on".
Then you will have to use Watt's Law to determine the power.