Magnetism and electromagnetism - class-X
Description: magnetism and electromagnetism | |
Number of Questions: 82 | |
Created by: Trisha Prashad | |
Tags: magnetism and electromagnetism electro-magnetism physics |
In the transformer phase difference between input and output is
Transformer are used
Why does the light of a car dim when the starter is operated?
Why is the iron core of a transformer laminated (thin sheet) instead of being in one solid piece?
In an electric motor, the energy transformation is:
Name the device used to transform 12 V a.c. to 200 V a.c. Name the principle on which it works.
A step-up transformer increases the AC voltage. The statement is
State whether true or false:
The transformer is used in ................. current circuits.
Name the material of core in electric bell, electromagnet, d.c. motor, a.c. generator and transformer.
What an electric device to stabilise voltage is called ?
Transformers are used
How will you relate the number of turns in the primary coil of a step-down transformer to that in secondary coil ?
What is the core of the transformer is made up of?
A transformer is employed to
In a step down transformer, the number of turns in the primary is always :
A transformer changes the voltage
Statement A: In a transformer, a large alternating current at low voltage can be transformed into a small alternating current at high voltage
Statement B: Energy in current carrying coil is stored in the form of magnetic field.
Transformers are used in
A transformer works on the principle of :
An ideal transformer has $500$ and $5000$ turns in primary and secondary winding respectively. If the primary coil is connected to a $6 V$ battery then the secondary voltage is
A step down transformer reduces $220V$ to $11V$. The primary coil draws $5 A$ current and secondary coil supplies $90A$. Efficiency of the transformer will be:
The device which is used for converting electrical energy into mechanical energy is called:
The principle on which transformer works is?
The AC produced in India changes Its direction in every:
A transformer is a device which gives :
A transformer:
A transformer is employed to ___________.
A transformer is
The best material for the core of a transformer is:
A transformer is used :
The best material for the core of a transformer is
In a step-up transformer, the turns ratio is $5 : 1$. The primary is connected to a battery of emf $10 V$. The voltage across secondary is ________.
A transformer works on the principle of __________.
A transformer
The purpose of a transformer is to do which of the following?
Complete the given statement, in order for a transformer to work:
Fill the vacant spaces with appropriate terms. The _______ going into a transformer is equal to the _______ going out of the transformer.
In a transformer, the immediate cause of the induced alternating current in the secondary coil is:
A transformer is used to:
A transformer uses iron core to .................... power loses.
The ratio of secondary to the primary tums in a transformer is $3:2.$ If the power out put be $P$, then input power, neglecting all losses, must be equal to:
An electric motor requires $220\ V$ of alternating current to run but the supplied alternating voltage is $100\ V$. Then the device used to run the motor is
The efficiency of a transformer is
A transformer is used to
Which of the remain constant in a transformer?
How are the e.m.f. in the primary and secondary coils of a transformer related with the number of turns in these coils?
For what purpose are the transformers used? Can they be used with a direct current source?
For what purpose are the transformers used ?
The input and output voltages of a transformer are $220$ V and $44$ V respectively. Find the turns ratio.
A transformer is used to light a $140W,24V$ bulb from a $240V$ a.c mains. The current in the main cable is $0.7A$. The efficiency of the transformer is
Assertion (A) : A transformer can’t work on dc.
Reason (R) : dc changes neither in magnitude nor in direction.
Statement A: Step up transformer converts low voltage, high current to high voltage, low current.
Statement B: Transformer works on both ac and dc.
Maximum efficiency of a transformer depends on :
A 220 - volt input is supplied to a Transformer. The output circuit draws a current of 2.0 ampere at 440 volts. If the efficiency of the transformer is 80%, the current drawn by the primary windings of the transformer is
Electrical energy is transmitted over large distance at high alternating voltages Which of the following statements is (are) correct?
A direct current (DC) motor is connected to a battery by means of two leads. The motor moves for slightly lessthan half the cycle and comes to halt. Which of the following components is missing?
Tum ratio in a step up transformer is 1 : 2 if a Lechlanche cell of 1.5 V is connected across the input, then the voltage across the output will be
Large transformers, when used for some time, become very hot and are cooled by circulating oil. The heating of the transformer is due to
A certain transformer has a turns ratio of 1 and a 0.85 coefficient of coupling. When 2 V ac is applied to the primary, the secondary voltage is
To step 120 V ac up to 900 V ac, the turns ratio must be
The primary winding of a power transformer should always be
State whether True or False :
State whether given statement is True or False
A transformer consists of two or more cores that are electrically coupled on a common core.
State whether given statement is True or False
An autotransformer is one in which the primary and secondary are automatically coupled.
In a transformer the number of turns in the primary coil is 200 and secondary coil is 600. The ratio between the electric current in the primary and secondary respectively is
In transformer, core is made of soft iron to reduce
The quantity that remains unchanged in the output with respect to the input in an ideal transformer is
Transformer works on.
A transformer is employed to
To increase the voltage of alternative current, we can use.
Which of the following has its working based on electromagnetic induction -
Read the following statements and answer whether the given statement is true or false.
A transformer works on both A.C. and D.C.
Why are transformers used in the transmission of electric power?
Which of the following statement about the action of a transformer is correct?
The current drawn by the primary of a transformer, which steps down 200 V to 20 V to operate a device of resistance 20 $\Omega$ is: (Assume the efficiency of the transformer to be 80 %)
In a step up transformer the turn ratio is 1:2. A Leclanche cell (emf = 1.5 V) is connected across the primary. The voltage across the secondary is
A transformer works on the principle of
Transformer is used to
Transformer can be used on;
The magnetic resonance imaging is used as a tool of diagnosis to detect the injuries in human body. It is based on the principle that: