Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

When a current flows through a conductor its temperature

  1. May increase or decrease

  2. Remains same

  3. Decreases

  4. Increases
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

According to Joule's heating effect of current, heat energy is generated across a conductor due to the current flowing through it and hence its temperature increases.

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

Heating effect of current is due to

  1. flow of voltage through the conductor.

  2. flow of current through a conductor.

  3. both A and B.

  4. neither A nor B.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Whenever an electric current is passed through a conductor, it gets heated up. And the amount of heat created is directly proportional to the square of the current.

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

Whenever an electric current is passed through a conductor,it gets heated up.this means that a part of electrical energy, given to the conductor, gets converted to

  1. potential energy

  2. gravitational energy

  3. heat energy

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Whenever an electric current is passed through a conductor,it gets heated up. This indicates that a part of electrical energy gets converted into heat energy.

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

Which of the following is/are energy efficient products?

  1. Tube lights

  2. Bulbs

  3. LEDs

  4. CFLs
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation

he electricity used over the lifetime of a single incandescent bulb costs 5 to 10 times the original purchase price of the bulb itself. Light Emitting Diode (LED) and Compact Fluorescent Lights (CFL) bulbs have revolutionized energy-efficient lighting. CFLs are simply miniature versions of full-sized fluorescents.

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

Why CFL is better in comparison to bulb ? 

  1. Because bulb produce heat which results in wastage of electricity and CFL saves electricity.

  2. Because bulb produce heat which results in production of more electricity than CFL

  3. Because CFLs size is bigger than bulb

  4. Because CFL produce heat which results in saving of electricity.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$1.$ Bulb work by heating up a small wire called a filament. Electric current heats the filament so much that it glows.

$2.$ This bulb really is more of a heating element that happens to put out some light.
$3.$ In fact, $90\%$ of the electricity used by a bulb is converted to heat and this conversion is wastage.
$4.$ Whereas, the CFL is just like standard fluorescent light, compact and work by exciting gases with electricity.
$5.$ Because little heat is generated, most of the electricity used goes directly into providing light.
So, since bulb produce more heat and results in wastage of electricity and CFL saves electricity, that"s why CFL is better in comparison to bulb.

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

Shivam went for buying a CFL from D-mart, what safety mark he should look for?

  1. Agmark

  2. ISI mark

  3. Trade mark

  4. Brand logo
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Shivam went for buying a CFL from D-mart,ISI safety mark he should look for
ISI mark is a certification mark for industrial products in India. The mark certifies that a product confirms to the Indian Standard(IS), mentioned as CM/L-xxxxxxx on top of the mark, developed by the Bureau of Indian Standards (BIS), the national standards body of India

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

Which of the following will produce maximum wastage of electricity ?

  1. CFL

  2. Electric bulb

  3. LED lights

  4. All are power savers
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Electric bulb works by heating up a small wire called a filament. Electric current heats the filament so much that it glow. In fact, $90\%$ of the electricity used by a electric bulb is converted to heat and this conversion will produce maximum wastage of electricity.

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

Several electric bulbs designed to be used on a 220 V electric supply are rated 20 W each. How many lamps can be connected in parallel with each other across the two wires of 220 V line, if the maximum allowable current is 5 A?

  1. 50

  2. 110

  3. 55

  4. 60
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total power P = V * I = 220 V * 5 A = 1100 W. Since each bulb is 20 W, the number of bulbs n = 1100 / 20 = 55.

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

An electric heater kept in vacuum is heated continuously by passing electric current. Its temperature:

  1. will go on rising with time

  2. will stop after sometime as it will loose heat to the surroundings by conduction

  3. will rise for sometime and thereafter will starts falling

  4. will become constant after sometime because of loss of heat due to radiation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Treating initially that there is no radiation and on applying voltage to the heater, the temperature of the heater rises. As the temperature rises, the radiation also increases.
As the input power($i^2r$) is constant, the output power should also be constant.
Initially temperature will be increasing and  radiation as well. When the heater reaches a certain temperature, the radiation power equals the input power and the temperature of the heater stops rising.
Thus temperature becomes constant after some time.