Question

1.

You need to insulate the wall with the below two materials. If you have 5 inch-thick plywood, how thick the softwood needs to be to meet the R-value of 9?

The following are R-values of common building insulation materials.

**Units of R-value are ft²-hr-ºF/Btu

Soft wood                                      R = 1 ( /1.25 inch )**

Plywood                                         R = 0.62 ( /0.5 inch)**

Group of answer choices

7.25 in

6.0 in

4.75 in

8.5 in

3.5 in

2.

If a 10 ohm and a 20 ohm resistor are wired in series to a 60 V source, what is the current (amps)?

Group of answer choices

3.2 A

2 A

2.4 A

6 A

1.5 A

3.

An electric iron has a resistance of 20 ohms and is connected to a 120 V wall socket. What is the power (W) consumed by the iron?

Group of answer choices

480 W

1800 W

720 W

8 W

960 W

4.

What is the power output of a wind turbine of blade radius 2 m in a 15 m/s wind?

Group of answer choices

0.6 kW

7.2 kW

15.2 kW

4.5 kW

2.5 kW

Answer 1