Tag: electric current and its effects

Quizzes (8) Questions (195)

Questions Related to electric current and its effects

Multiple choice physics electric current and its effects coil and fuse heating effect of electric current- uses applications of heating effect of electric current

Two equal resistance when connected in series to a battery, consume electri power  of 60 w.  If these resistnce are now  connected in parallel combination to  the same battery the electric power consumed will be 

  1. 60 W

  2. 240 W

  3. 30 W

  4. 120 W
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When two equal resistors of resistance R are in series, the equivalent resistance is 2R and power is V^2 / (2R) = 60 W. When connected in parallel, the equivalent resistance is R/2, so the power becomes V^2 / (R/2) = 4 * (V^2 / 2R) = 4 * 60 W = 240 W.

Multiple choice physics electric current and its effects coil and fuse heating effect of electric current- uses applications of heating effect of electric current

Why filament of electric bulb is made of tungsten

  1. Melting Point of filament is very high

  2. Resistance of filament is very less

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The resistance of filament should be high so that it can produce heat and light and its melting point should also be high so that it does not melt at the high temperature at which it is producing light.


Answer-(A)

Multiple choice physics electric current and its effects coil and fuse heating effect of electric current- uses applications of heating effect of electric current

The operating temperature of the filament of lamp is ${ 2000 }^{ 0 }C$. The temperature coefficient of the material of filament is ${ 0.005 }^{ 0 }{ C }^{ -1 }$. If the atmospheric temperature is ${ { 0 }^{ 0 }C }$, then the current in the 100W-200W lamp when it is switched on is nearest to 

  1. 2.5 A

  2. 3.5 A

  3. 4.5 A

  4. 5.5 A
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The resistance of the filament varies with temperature. At operating temperature (2000°C), R_hot = V²/P = 220²/100 = 484Ω. Using the temperature coefficient formula: R_cold = R_hot/(1 + α(2000-0)) = 484/(1 + 0.005×2000) = 484/11 = 44Ω. Initial current = V/R_cold = 220/44 = 5A. However, this is an approximation - the actual surge current depends on how quickly the filament heats up. Given the options, 4.5A is the closest reasonable estimate.

Multiple choice physics electric current and its effects electric bell the magnetic effect of a current current electricity and magnetism

An electric bell has a resistance of $5 \Omega$ and requires a current of $0.25\ A$ to work it. Assuming that the resistance of the bell wire is $1 \Omega$ per $15m$ and that the bell push is $90m$ distance from the bell. How many cells each of emf $1.4V$ and internal resistance $2 \Omega$, will be required to work the circuit.

  1. $3$
  2. $4$
  3. $5$
  4. $Can't\ be\ determined$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total resistance = R_bell + R_wire = 5 + (90/15)*1 = 11 ohms. Current = 0.25A. Total EMF required = I * R_total = 0.25 * (11 + n*r_internal). Solving for n with 1.4V cells.

Multiple choice physics electric current and its effects heating effect of electric current- uses applications of heating effect of electric current coil and fuse

The heating element in an electric iron is made up of :

  1. nichrome

  2. iron

  3. constantan

  4. tungsten
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Answer is A.

Most heating elements use Nichrome 80/20 (80% nickel, 20% chromium) wire, ribbon, or strip. Nichrome 80/20 is an ideal material, because it has relatively high resistance and forms an adherent layer of chromium oxide when it is heated for the first time. Material beneath this layer will not oxidize, preventing the wire from breaking or burning out.
Hence, nichrome is used as heating elements.

Multiple choice physics electric current and its effects heating effect of electric current- uses applications of heating effect of electric current coil and fuse

An electric iron is based upon the principle of

  1. heating effect ofcurrent

  2. magnetic effect ofcurrent

  3. chemical effect ofcurrent

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

An electric iron is based on the principle of heating effect of current that heat is produced in the nichrome wire used in the iron due to the current flowing through it.

Multiple choice physics electric current and its effects heating effect of electric current- uses applications of heating effect of electric current coil and fuse

The overheating of electrical wiring in any circuit due to the flow of large current through it is called _________ of the electric circuit.

  1. over heating

  2. heating effect

  3. cooling effect

  4. see-back effect
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The overheating of electrical wiring in any circuit due to the flow of large current through it is called overloading of electric current.