Advertisements
Advertisements
प्रश्न
A step-down transformer connected to the main supply of 220 V is used to operate 11V,88W lamp. Calculate
- Voltage transformation ratio and
- Current in the primary
Advertisements
उत्तर
Given data:
Vp = 220 V, Ps = 88 W, Vs = 11 V
Transformation ratio K = `"V"_"s"/"V"_"p"`
K = `11/220 = 1/20 = 1 : 20 = 1/20`
Current in the primary Ip = ?
`"P"_"S" = "V"_"S" "I"_"S"`
`"I"_"S" = "P"_"S"/"V"_"S" = 88/11` = 8 A
`therefore "I"_"p"/"I"_"S" = "K"`
`"I"_"p" = "KI"_"S"`
`therefore "I"_"p" = 1/20 xx 8 = 2/5 = 0.4`
Ip = 0.4 A
APPEARS IN
संबंधित प्रश्न
You are required to make an electromagnet from a soft iron bar by using a cell, an insulated coil of copper wire and a switch. (a) Draw a circuit diagram to represent the process. (b) label the poles of the electromagnet.
Draw a labeled diagram of a full wave rectifier circuit. State its working principle. Show the input-output waveforms ?
State the factors on which the frequency of the alternating e.m.f. depends.
Describe the construction and working of a transformer with a neat labelled diagram.
A step-up transformer has 300 turns of primary winding and 450 turns of secondary winding. A primary is connected to 150 V and the current flowing through it is 9A. The current and voltage in the secondary are
Assertion: A transfonner cannot work on D.C. supply.
Reason: D.C. changes neither in magnitude nor in direction.
A 100% efficient transformer has 100 turns in the primary and 50 turns in its secondary coil. If the current in the secondary coil is 6 A, then the current in the primary coil is ______.
The primary winding of a transformer has 100 turns and its secondary winding has 200 turns. The primary is connected to an a.c supply of 120 V and the current flowing in its is 10 A. The voltage and the current in the secondary are ______.
For an LCR circuit, the power transferred from the driving source to the driven oscillator is P = I2Z cos φ.
- Here, the power factor cos φ ≥ 0, P ≥ 0.
- The driving force can give no energy to the oscillator (P = 0) in some cases.
- The driving force cannot syphon out (P < 0) the energy out of oscillator.
- The driving force can take away energy out of the oscillator.
Two coils P and Q are kept near each other. When no current flows through coil P and current increase in coil Q at the rate 10A/s, the emf in coil P is 15mV. When coil Q carries no current and current of 1. 8A flows through coil P, the magnetic flux linked with the coil Q is ______.
