Physics
The given diagram shows the output of an AC generator. If the speed of the generator coil is doubled, then:
(a) what is the effect on the physical quantity indicated by ‘a’?
(b) what is the effect on the physical quantity indicated as ‘b’?
(c) give reason for your answer in (b).
Answer
(a) As, the physical quantity indicated by 'a' is induced emf or output voltage of the a.c. generator so on doubling the speed of the generator, the output voltage also gets doubled.
(b) As, the physical quantity indicated by 'b' is time period of the generator so on doubling the speed, the period becomes half.
(c) When in an a.c generator the speed at which the coil rotates is doubled the frequency of output voltage is also doubled and since time period is reciprocal of the frequency so it gets halved.
Related Questions
An appliance with a metal covering, rated at 2 kW, 220 V, is to be connected in a circuit. Given below are four diagrams (P, Q, R & S) depicting different circuit configurations.
(a) Identify the safest circuit.
(b) Write two reasons, supported by mathematical calculations, where applicable, to justify your choice.
A nichrome wire X with length (l) & cross-sectional area (A) is connected to a 10 V source and another nichrome wire Y with length (2l) & cross-sectional area (A/2), is connected to a 20 V source.
(a) Compare the resistances of wires X and Y. [Given that the resistivity of nichrome is (ρ).]
(b) Compare the electrical power consumed by each wire.
(c) Compare the masses of these wires. (Given that the density of nichrome is d.)
(d) State True or False : Wire X and wire Y both show the same rise in temperature in the same time.
Three bulbs of powers P1, P2 and P3 (P1 < P2 < P3) are connected in a certain way that P3 glows brightest.
(a) What type of connection exists between these bulbs?
(b) Compare the voltage across these bulbs. (Use >, < or =)
(c) Will the circuit still function if one of the bulbs is fused?
The graph (Fig. A) illustrates the correlation between the number of protons (x-axis) and the number of neutrons (y-axis) for elements A, B, C, D, and E in the periodic table. These elements are denoted by the letters rather than their conventional symbols.
(a) Identify the radioactive radiation emitted when element C decays into element E. Represent this using a nuclear reaction.
(b) What is the special name given to elements D and E?
(c) If element C transforms into element B by emitting a radioactive ray, how will this ray behave in an electric field?