Which of the following materials does not serve as a safety device in electrical circuits?
Connecting wires
Earth wire
Fuse
Switch
Correct answer is A
No explanation has been provided for this answer.
In the diagram above, the time taken to trace a wave between P and Q is?
2 periods
1 period
112 periods
114 periods
Correct answer is A
frequency means no of oscillation per secs, so the time taken to trace a wave between p and q is 2secs.
Which of the following thermometers is used to measure the temperature of the human body?
Thermocouple
Alcohol-in-glass thermometer
Gas thermometer
Platinum resistance thermometer
Correct answer is B
The range of usefulness of the thermometer is set by the boiling point of the liquid used. In the case of the ethanol-filled thermometer, the upper limit for measurement is 78 °C (172.4 °F), which makes it useful for measuring daytime, nighttime and body temperatures, although not for anything much hotter than these.
1.6 x 10−9N
1.3 x 103N
2.3 x 103N
5.0x 103N
Correct answer is A
Using the formula
F = Gm1m2r2
= 6.67×10−11×3.0×2.0(50)2
= 40.02×10−112500
= 1.6 x 10−9N