All Free Everyday Science MCQs with Answers

1901. In the electricity meter the digit to the extreme right is___________?

• A. 1/5th of the unit
• B. 1/100 of the unit
• C. 1/10th of the unit
• D. 1/1000th of the unit

Explanation: In the conventional household electricity meter described here, the extreme-right digit records tenths of a kilowatt-hour, so it represents 1/10 of a unit. Digital meters may show different decimal resolutions, but the traditional meter convention gives this answer.

1902. Units of electricity consumed by 2500 watt air-conditioner in one hour are_________?

• A. 25 units
• B. 2.25 units
• C. 2.5 units
• D. 0.25 units

Explanation: Convert 2500 watts to 2.5 kilowatts, then multiply by one hour: 2.5 kW × 1 h = 2.5 kWh. Since one electricity unit equals one kilowatt-hour, the consumption is 2.5 units.

1903. According to the definition of 1 KWh, a 100 watt bulb consumes one unit of electricity in_________?

• A. 2 hours
• B. 5 hours
• C. 8 hours
• D. 10 hours

Explanation: A 100-watt bulb uses 0.1 kilowatt, so it requires 10 hours to consume 1 kilowatt-hour, or one unit of electricity.

1904. The large plates of solar pannels are painted?

• A. Red
• B. White
• C. Yellow
• D. Black

Explanation: Solar panels are painted black because black surfaces absorb the maximum amount of incoming sunlight and convert more of it into heat or electrical energy.

1905. In which system of units, gas bills are charged?

• A. SI
• B. CGS
• C. BTU
• D. CNG

Explanation: Gas consumption is commonly expressed for billing in British thermal units, especially larger units such as MMBTU. SI and CGS are general measurement systems, while CNG is a fuel, not a unit.

1906. In BTU system, one BTU is equal to__________?

• A. 2055 Joule
• B. 1155 Joule
• C. 2155 Joule
• D. 1055 Joule

Explanation: One British thermal unit is approximately equal to 1,055 joules, representing the heat needed to raise one pound of water by one degree Fahrenheit.

1907. Heating element of an electric heater is made up of___________?

• A. Tungsten
• B. Graphite
• C. Chromium
• D. Nichrome

Explanation: Electric heaters use nichrome, an alloy with high electrical resistance and a high melting point. Its resistance converts electrical energy into heat without melting quickly.

1908. Telephone was invented by__________?

• A. Vint Cerf
• B. Charles Babbage
• C. Edison
• D. Alexander Graham Bell

Explanation: Alexander Graham Bell is credited with inventing and patenting the practical telephone in 1876. Edison made major contributions to electrical technology but was not the telephone's inventor.

1909. UPS is now widely use in households. What does UPS stands for ?

• A. Uniform Power Storage
• B. Universal Product Support
• C. Under Panel Storage
• D. Uninterruptible Power Supply

Explanation: UPS means Uninterruptible Power Supply, a device that provides temporary backup electricity when the main supply fails. It also helps protect equipment from some voltage disturbances.

1910. Which element is used as moderator in nuclear reactor?

• A. Light water
• B. Dense water
• C. Fresh water
• D. Heavy water

Explanation: Heavy water is used as a moderator in some nuclear reactors because its deuterium slows fast neutrons while absorbing relatively few of them. Light water can also moderate certain reactors, so the question is simplified but d is the intended choice.