Electricity

31.If a 100 watts bulb is used for 10 hours, then the amount of consumed electrical energy will be –
 
A. 100 Watts
 
B. 100 Watts per hour
 
C. 1000 Watts (1 KW)
 
D. 1 KWh (1 unit of electricity)
 
Option “D” is correct.

Given that
Power of the bulb = 100 W
Time = 10 hours
We know that,

Energy = Power × Time

⇒ Energy consume = 100 w × 10 hrs = 1000 watt – hr = 1 KWh.

32.Who invented the lightning conductor?
 
A. Graham Bell
 
B. Lord lister
 
C. Benjamin Franklin
 
D. Einstein
 
Option “C” is correct.
Lightning conductor is a metal rod usually placed atop high towers and buildings to prevent damage caused by the direct hit of a lightning. The metal rod collects charges and directs it to the earth. It was invented by Benjamin Franklin in 1749.
33.Lightning conductors are made __
 
A. of iron
 
B. of aluminum
 
C. of copper
 
D. of steel
 
Option “C” is correct.
A lightning conductor is made of copper because copper is a good conductor of electricity.
34.Given below are statements ‘A’ and ‘R’. Study and select the correct answer from the codes given below – Assertion (A) : Lightning conductors protect buildings from destruction. Reason (R) : They conduct charge to earth. Code :
 
A. Both A and R are correct and R is the correct reason for A.
 
B. Both A and R are true, but R is not the correct reason for A.
 
C. A is correct but R is incorrect
 
D. A is wrong, but R is correct.
 
Option”A” is correct
35.When current is passed through an electric bulb, its filament glows, but the wire leading current to the bulb does not glow because :
 
A. Less current flows in the leading wire as compared to that in the filament
 
B. The leading wire has more resistance than the filament
 
C. The leading wire has less resistance than the filament
 
D. Filament has coating of fluorescent material over it
 
Option “C” is correct.
The leading wire is usually made with conductors such as copper and aluminium, therefore have less resistance than the filament which is usually made with tungsten and has a high resistance.
Due to this the power lost P =I^2R is greater for filament which is visible as light(and also heat).
36.Which one of the following non-metals is not a poor conductor of electricity?
 
A. Sulphur
 
B. Selenium
 
C. Bromine
 
D. Phosphorus
 
Option “B” is correct.
Metal which is a poor conductor of heat is: Q. Which one of the following non-metals is not a poor conductor of electricity? Generally, non-metals are not conductors of electricity.
37.Which of the following are used as electrolytes in dry cell?
 
A. Ammonium chloride and zinc chloride
 
B. Sodium chloride and calcium chloride
 
C. Magnesium Chloride and Zinc Chloride
 
D. Ammonium chloride and calcium chloride
 
Option “A” is correct.
A standard dry cell comprises a zinc anode, usually in the form of a cylindrical pot, with a carbon cathode in the form of a central rod. The electrolyte is ammonium chloride in the form of a paste next to the zinc anode.
38.Which one of the following is printed on a commonly used fluorescent tube light?
 
A. 220K
 
B. 273K
 
C. 6500K
 
D. 9000K
 
Option “C” is correct
39.Normally the human body resistance in totally wet and dry condition is ________ respectively.
 
A. 1 kΩ and 1 MΩ
 
B. 0.1 Ω and 10 kΩ
 
C. 100 Ω and 1 kΩ
 
D. 100 Ω and 10 kΩ
 
Option “A” is correct.
Under dry conditions, the resistance offered by the human body may be as high as one mega ohms. Wet or broken skin may drop the body’s resistance to 1000 ohms. Adding that, high-voltage electrical energy quickly breaks down human skin, reducing the human body’s resistance to 500 ohms.
40.Which metal is used to generate electricity?
 
A. Cotton
 
B. Iron
 
C. Copper
 
D. Aluminum
 
Option “C” is correct.
One of the most commonly used metals to conduct electricity is copper. As a material, copper is pliable, easy to wrap or solder, which makes it the best choice when large amounts of wiring are needed. Copper’s core electrical function is related to the transmission of electricity and power generation

Pages: 1 2 3 4 5 6 7 8 9 10