Advertisements
Advertisements
प्रश्न
Is energy produced when a transformer steps up the voltage?
Advertisements
उत्तर
When a transformer steps up the voltage, the voltage increases but current decreases. Neglecting any loss of energy, the power remains constant and, hence, energy is not produced. It remains constant.
APPEARS IN
संबंधित प्रश्न
Show that the current leads the voltage in phase by π/2 in an AC circuit containing an ideal capacitor ?
When an AC source is connected to a capacitor, there is a steady-state current in the circuit. Does it mean that the charges jump from one plate to the other to complete the circuit?
A capacitor acts as an infinite resistance for ______.
An AC source producing emf ε = ε0 [cos (100 π s−1)t + cos (500 π s−1)t] is connected in series with a capacitor and a resistor. The steady-state current in the circuit is found to be i = i1 cos [(100 π s−1)t + φ1) + i2 cos [(500π s−1)t + ϕ2]. So,
The peak voltage of a 220 V AC source is
An AC source is rated 220 V, 50 Hz. The average voltage is calculated in a time interval of 0.01 s. It
The AC voltage across a resistance can be measured using
A bulb rated 60 W at 220 V is connected across a household supply of alternating voltage of 220 V. Calculate the maximum instantaneous current through the filament.
A transformer has 50 turns in the primary and 100 in the secondary. If the primary is connected to a 220 V DC supply, what will be the voltage across the secondary?
Compare resistance and reactance.
When an ac voltage of 220 V is applied to the capacitor C, then ______.
A capacitor has capacitance C and reactance X, if capacitance and frequency become double, then reactance will be ______.
Explain why the reactance provided by a capacitor to an alternating current decreases with increasing frequency.
In the LCR circuit shown in figure, the ac driving voltage is v = vm sin ωt.
- Write down the equation of motion for q (t).
- At t = t0, the voltage source stops and R is short circuited. Now write down how much energy is stored in each of L and C.
- Describe subsequent motion of charges.

An iron cored coil is connected in series with an electric bulb with an AC source as shown in figure. When iron piece is taken out of the coil, the brightness of the bulb will ______.

When an AC voltage of 220 V is applied to the capacitor C ______.
The resistance of a coil for d.c. is 5 Ω. In a.c., the resistance will ______.
