Advertisements
Advertisements
प्रश्न
Write the two names in the following diagram.
Right hand thumb rule.
Advertisements
उत्तर
APPEARS IN
संबंधित प्रश्न
State Fleming’s right-hand rule.
When a bar magnet is pushed towards (or away) from the coil connected to a galvanometer, the pointer in the galvanometer deflects. Identify the phenomenon causing this deflection and write the factors on which the amount and direction of the deflection depends. State the laws describing this phenomenon.
What is electromagnetic induction?
How does an electromagnet differ forma permanent magnet?
When current is 'switched on' and 'switched off' in a coil, a current is induced in another coil kept near it. What is this phenomenon known as?
What do you understand by the term "electromagnetic induction"? Explain with the help of a diagram.
Name one device which works on the phenomenon of electromagnetic induction.
When the magnet shown in the diagram below is moving towards the coil, the galvanometer gives a reading to the right.
() What is the name of the effect being produced by the moving magnet?
(2) State what happens to the reading shown on the galvanometer when the magnet is moving away from the coil.
(3) The original experiment is repeated. This time the magnet is moved towards the coil at a great speed. State two changes you would notice in the reading on the galvanometer.
In which of the following case does the electromagnetic induction occur?
The current is stopped in a wire held near a loop of wire .
In which of the following case does the electromagnetic induction occur?
A loop of wire is held near a magnet.
Welders wear special goggles or face masks with glass windows to protect their eyes from electromagnetic radiations. Name the radiations and write the range of their frequency.
The switches in figure (a) and (b) are closed at t = 0 and reopened after a long time at t = t0.
(a) The charge on C just after t = 0 is εC.
(b) The charge on C long after t = 0 is εC.
(c) The current in L just before t = t0 is ε/R.
(d) The current in L long after t = t0 is ε/R.
The diagram 10 shows two coils X and Y. The coil X is connected to a battery S and a key K. The coil Y is connected to a galvanometer G.
When the key K is closed. State the polarity
(i)At the end of the coil X,
(ii)At the end C of the coil Y,
(iii)At the end C of the coil Y if the coil Y is (a) Moved towards the coil X, (b) Moved away from the coil X.
The following diagram shows a fixed coil of several turns connected to a center zero galvanometer G and a magnet NS which can move in the direction shown in the diagram.
- Describe the observation in the galvanometer if
- The magnet is moved rapidly,
- The magnet is kept still after it has moved into the coil
- The magnet is then rapidly pulled out the coil.
- How would the observation in (i) of part (a) change if a more powerful magnet is used?
Draw and label the diagram of a simple D.C. motor.
(a) Explain the rotation of the coil, giving a reason for your answer.
(b) How can you reverse the direction of rotation of the armature?
(c) How can you increase the speed of rotation of the motor?
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
A. C. generator______.
Draw a labelled diagram to show how an electromagnet is made.
State the purpose of soft iron core used in making an electromagnet.
List some of the practical applications of an electromagnet.
Observe the given figure of Fleming’s Right Hand Rule and write the labels of A and B correctly.
The right-hand thumb rule is also called _______ rule.
A thin semi-circular conducting ring (PQR) of radius r is falling with its plane vertical in a horizontal magnetic field B, as shown in the figure.
The potential difference developed across the ring when its speed v , is
What for an inductor is used? Give some examples.
Obtain an expression for motional emf from Lorentz force.
Metal rings P and Q are lying in the same plane, where current I is increasing steadily. The induced current in metal rings is shown correctly in figure.
A cylindrical bar magnet is kept along the axis of a circular coil. If the magnet is rotated about its axis, then ____________.
A metal plate can be heated by ______.
The condition for the praenomen of electromagnetic induction is that there must be a relative motion between ____________.
The instrument that use to defect electric current in the circuit is known as ____________.
Ansari Sir was demonstrating an experiment in his class with the setup as shown in the figure below.
A magnet is attached to a spring. The magnet can go in and out of the stationary coil. He lifted the Magnet and released it to make it oscillate through the coil.
Based on your understanding of the phenomenon, answer the following question.
What will be observed when the Magnet starts oscillating through the coil. Explain the reason behind this observation.
Name some equipment that uses electromagnetism for functioning.
A conducting bar of length L is free to slide on two parallel conducting rails as shown in the figure
Two resistors R1 and R2 are connected across the ends of the rails. There is a uniform magnetic field `vec"B"` pointing into the page. An external agent pulls the bar to the left at a constant speed v. The correct statement about the directions of induced currents I1 and I2 flowing through R1 and R2 respectively is:
One solenoid is centered inside another. The outer one has a length of 50.0 cm and contains 6750 coils, while the coaxial inner solenoid is 3.0 cm long and π cm2 in area and contains 150 coils. The current in the outer solenoid is changing at 3000 A/s. The emf induced in the inner solenoid is ______ V.
(Round off to two decimal places.)
In the current carrying conductor (AOCDEFG) as shown, the magnetic induction at point O is ______.
(R1 and R2 are radii of CD and EF respectively. l = current in the loop, μ0 = permeability of free space)
