मराठी
कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान इयत्ता ११

Is Energy Produced When a Transformer Steps up the Voltage?

Advertisements
Advertisements

प्रश्न

Is energy produced when a transformer steps up the voltage?

टीपा लिहा
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.

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 39: Alternating Current - Short Answers [पृष्ठ ३२९]

APPEARS IN

एचसी वर्मा Concepts of Physics Volume 1 and 2 [English]
पाठ 39 Alternating Current
Short Answers | Q 10 | पृष्ठ ३२९

संबंधित प्रश्‍न

A 2 µF capacitor, 100 Ω resistor and 8 H inductor are connected in series with an AC source.
(i) What should be the frequency of the source such that current drawn in the circuit is maximum? What is this frequency called?
(ii) If the peak value of e.m.f. of the source is 200 V, find the maximum current.
(iii) Draw a graph showing variation of amplitude of circuit current with changing frequency of applied voltage in a series LRC circuit for two different values of resistance R1 and R2 (R1 > R2).
(iv) Define the term 'Sharpness of Resonance'. Under what condition, does a circuit become more selective?


A current i1 = i0 sin ωt passes through a resistor of resistance R. How much thermal energy is produced in one time period? A current i2 = −i0 sin ωt passes through the resistor. How much thermal energy is produced in one time period? If i1 and i2 both pass through the resistor simultaneously, how much thermal energy is produced? Is the principle of superposition obeyed in this case?


A transformer is designed to convert an AC voltage of 220 V to an AC voltage of 12 V. If the input terminals are connected to a DC voltage of 220 V, the transformer usually burns. Explain.


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 i1 cos [(100 π s−1)t + φ1) + i2 cos [(500π s−1)t + ϕ2]. So,


The AC voltage across a resistance can be measured using


The dielectric strength of air is 3.0 × 106 V/m. A parallel-plate air-capacitor has area 20 cm2 and plate separation 0.10 mm. Find the maximum rms voltage of an AC source that can be safely connected to this capacitor.


Compare resistance and reactance.


Suppose the initial charge on the capacitor is 6 mC. What is the total energy stored in the circuit initially? What is the total energy at later time?


If circuit containing capacitance only, the current ______.


A.C. power is transmitted from a power house at a high voltage as ______.


The frequency of A.C. mains in India is ______.

When an AC voltage of 220 V is applied to the capacitor C ______.

  1. the maximum voltage between plates is 220 V.
  2. the current is in phase with the applied voltage.
  3. the charge on the plates is in phase with the applied voltage.
  4. power delivered to the capacitor is zero.

A device ‘X’ is connected to an a.c source. The variation of voltage, current and power in one complete cycle is shown in figure.

  1. Which curve shows power consumption over a full cycle?
  2. What is the average power consumption over a cycle?
  3. Identify the device ‘X’.


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 ______.


An a.c. source generating a voltage ε = ε0 sin ωt is connected to a capacitor of capacitance C. Find the expression for the current I flowing through it. Plot a graph of ε and I versus ωt to show that the current is ahead of the voltage by π/2.


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 ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×