# Science 9 1-4, 2-1 and 2-2 27 and 28 March 2017

Finish the power and energy questions given in class (from BC Science). Be sure to follow the steps we used in class.

In case you didn’t finish in class, the last few questions are below.

4. What is the current through a 6.0 W bulb when it is connected to a 1.5 V battery?

5. (a) A 40 W bulb is connected to a power supply and draws a current of 0.75 A. What is the voltage of the power supply?

5. (b) IF the 40 W light bulb is replaced by a 100 W light bulb, how much current will flow through the 100 W bulb? (Hint: Use the voltage found in part (a))

6. What is the power, in watts, of an unknown device, if a current of 35 mA flows through the device when it is connected to 3.0 V?

7.  How much energy, in joules, is consumed by a 120 W light bulb if it is left on for 15 mins?

8. How much energy, in joules, is consumed by a 1400 W hair dryer if it is used for 10 mins?

9. How much energy, in joules, is consumed by a 200 W stereo if it is left on for 4.0 h?

Be sure to bring a calculator (cell phones cannot be used as calculators), textbook and workbook.

Assigned before Spring break: Read 9.2 in text and do 9.2 in workbook.