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Multiple choice physics alternating currents sinusoidal current types of current movement of charge

Choose the correct statements from the following $A.C.$ cannot be used in

  1. Electroplating

  2. Charging a battery

  3. Charging a capacitor

  4. Electrolysis

  5. Heating a room
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electroplating and electrolysis require a constant unidirectional current (DC) to ensure metal ions are deposited consistently on the cathode. AC would cause the ions to oscillate back and forth, preventing successful plating.

Multiple choice physics alternating currents sinusoidal current types of current movement of charge

In alternating current

  1. The direction of current is always positive

  2. The direction of current is always negative

  3. The direction of current changes constantly

  4. The direction of current is either positive or negative
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

C

Electric charge in alternating current (AC) changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction.

 

Multiple choice physics alternating currents sinusoidal current types of current movement of charge

In an A.C. circuit a resistance R is connected in series with an inductance L.The phase difference between voltage and current is $45^o$. Then what will be the value of inductive reactance?

  1. R

  2. $\frac{R}{2}$

  3. $\frac{R}{4}$

  4. 2R
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In an R-L series circuit, the phase difference is given by tan(phi) = X_L / R. Since phi = 45 degrees, tan(45) = 1, which implies X_L / R = 1, or X_L = R.