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

From below which are the applications of heating effect of electric current?

  1. Electric immersion water heater

  2. Electric Iron Box

  3. Electric Fuse

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

According to heating effect of electric current, heat is produced in the materials that have resistance, thus electric immersion water heater, electric iron box and electric fuse are the applications of heating effect of electric current.

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 are bulbs filled with chemically inactive Nitrogen or Argon gas?

  1. To prevent oxidation of Tungsten filament

  2. To prevent dehydration of Tungsten filament

  3. To prevent oxidation of Steel filament

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

Bulbs are filled with chemically inactive Nitrogen or Argon gas to prevent the oxidation of tungsten filament used in the bulb.

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

An electric fuse used in households works on which principle of:

  1. Joule's heating

  2. Coulomb's law

  3. Maxwell's law

  4. Ohm's law
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An electric fuse in households works on the principle of Joule's heating that heat produced due to the excess current flowing through it melts the fuse wire which cut off the circuit and hence the appliance is prevented from damage.

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 is electric power transmitted over long distances at high voltage?

  1. To minimize power loses due to Joule's heating

  2. To maximize power loses due to Joule's heating

  3. To balance power loses due to Joule's heating

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

For constant electric power, higher the voltage, lower is the current (as $P=IV$) through the wire. As power loss due to Joule's heating is proportional to $I^2$, for a small current, power loss is also small. So, power is transmitted over long distances at high voltage to minimize power loses due to Joule's heating.

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

A vertical wire caries a current in upward direction. An electron beam sent horizontally towards the wire will be deflected

  1. towards right

  2. towards left

  3. upwards

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

Using Right-Hand thumb rule and (Flemmings Left Hand Rule, current direction (i) = Left Side Magnetic field  (B) = outwards, so the direction of the force is upwards.

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

When a metallic conductor is heated then the atoms in the metal vibrate with ?

  1. low amplitude and frequency.

  2. greater amplitude and frequency.

  3. greater amplitude and low frequency.

  4. less amplitude and greater frequency.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When a metallic conductor is heated its atoms get more energy and get agitated. That is why they vibrate with greater amplitude and frequency.

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

Thermal energy produced by the resistance R in time duration 1 $ \mu s $. using the source at resonance condition is 

  1. 0 J
  2. $ 1 \mu J $
  3. $ 100 \mu J $

  4. not possible to calculate from the given information.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

To calculate thermal energy produced by resistance, we need the current through the resistance, which requires knowledge of the circuit components (voltage source, impedance at resonance, circuit configuration). The question states 'using the source at resonance condition' but provides no numerical values for voltage, current, resistance, frequency, or circuit parameters. Without this information, the energy cannot be calculated.

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

Current through resistor of resistance $R$ varies with time as $I = I _ot$. What will be the time taken to deliver heat $H$ by this resistor?

  1. $\left( \cfrac { H } { I _ { 0 } R } \right) ^ { 1 / 2 }$
  2. $\left( \cfrac { H } { 3 I _ { 0 } ^ { 2 } R } \right) ^ { 1 / 3 }$
  3. $\left( \cfrac { 3 H } {I _ { 0 } ^ { 2 } R } \right) ^ { 1 / 3 }$
  4. $\left( \cfrac { H } { I _ { 0 } ^ { 2 } R } \right) ^ { 1 / 3 }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Heat produced is H = ∫I²R dt. Given I = I₀t, we have H = ∫(I₀t)²R dt from 0 to T. This gives H = I₀²R∫t²dt = I₀²R(T³/3). Solving for time T: T³ = 3H/(I₀²R), so T = (3H/(I₀²R))^(1/3). This matches option C.

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

If p.d. across a conductor is constant and resistivity of its material is $\rho $, the joule heat produced in 1 s is proportional to .. 

  1. $\dfrac{1}{\rho }$
  2. $\dfrac{1}{{\sqrt \rho }}$
  3. $\rho $
  4. ${{\rho ^2}}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Joule heat in 1 second is H = V²/R (since P.d. is constant). Resistance of a conductor is R = ρL/A, where L is length and A is cross-sectional area. For a fixed geometry (L and A constant), R ∝ ρ. Therefore H = V²/R ∝ 1/R ∝ 1/ρ. The heat produced is inversely proportional to resistivity.

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

A coal based thermal power plant producing electricity operates between the temperatures $27^o C$ and $227^o C$ The plant works at 80% of its maximum theoretical efficiency. Complete burring of 1 kg of coal yields 3600 KJ of heat. A house needs 10 units of electricity each day. Coal used for supplying the amount of energy for the house in one year is 

  1. 1141 kg

  2. 580 kg

  3. 605 kg

  4. 765 kg
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Carnot efficiency: η_max = 1 - T_c/T_h = 1 - 300/500 = 0.4. Actual efficiency at 80%: η = 0.4 × 0.8 = 0.32. Yearly electricity needed: 10 × 365 = 3650 units. Each unit requires energy. With 3600 kJ/kg coal and 32% efficiency, usable energy per kg = 3600 × 0.32 = 1152 kJ/kg. Converting units to kJ and calculating: Coal needed ≈ 3650 × (energy per unit in kJ)/(1152) ≈ 580 kg after unit conversions.