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प्रश्न
A flat coil of wire rotates at a constant speed about an axis perpendicular to a uniform magnetic field. Draw a graph to show how the induced e.m.f. varies relative to the positions of the coil during its one complete rotation. At what position of the coil, the e.m.f. has the maximum value?
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उत्तर
Figure below shows the variation in induced e.m.f. relative to various positions of coil, during its one complete rotation.
The e.m.f. is maximum when the coil is with its plane parallel to the magnetic field.
V = Coil vertical
H = Coil Horizontal
संबंधित प्रश्न
What type of generator is used at Power Stations?
Each one of the following changes will increase emf (or voltage) in a simple generator except:
(a) increasing the number of turns in the armature coil
(b) winding the coil on a soft iron armature
(c) increasing the size of the gap in which the armature turns
(d) increasing the speed of rotation
A d.c. generator is based on the principle of:
(a) electrochemical induction
(b) electromagnetic induction
(c) magnetic effect of current
(d) heating effect of current
In an a.c. generator the speed at which the coil rotates is doubled. How would this affect
- the frequency of output voltage,
- the maximum output voltage is doubled.
State change that you would make to convert an A.C. generator into a D.C. generator. Illustrate the change by a diagram.
The given figures 1 to 3 show the working of a simple A.C. generator. Study the diagrams and answers of the following questions.
(i) State and explain the principle underlying the working of a simple generator.
(ii) Where is the loop of wire placed?
(iii) What happens when the loop is rotated?
(iv) Indicate the direction of the current flow through the wire for the first half of the turn (in first figure). Name and state the rule used in finding the direction of the current.
(v) Indicate the direction of the current for the case shown in second figure.
(vi) Indicate the direction of current in the outer circuit (i.e., electric bulb) in first and third figure.
(vii) What type of current is shown in the above diagrams? Explain.
State true or false:
The frequency of AC is 50 Hz.
Observe the figure and write the answers to the questions asked.
- The construction shown in the figure is of which device?
- Explain the principle on which this device works.
- Write any three uses of this device.
Draw a neat diagram of an AC generator and explain its working.
A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is held stationary inside the coil?
