Advertisements
Advertisements
Question
The substance having infinitely high electrical resistance is called:
(a) conductor
(b) resistor
(c) superconductor
(d) insulator
Advertisements
Solution
(d) insulator
A substance having infinitely high electrical resistance is called an insulator.
APPEARS IN
RELATED QUESTIONS
In series combination which remains constant?
(a) Voltage
(b) Current
(c) Both current and voltage
(d) Both are variables
If the equivalent resistance is to be increased, then the number of resistances should be connected in
- Series
- Parallel
- Mixed arrangement
- None of the above
Write any two characteristics of a series combination of resistors.
(i) Two sets A and B, of three bulbs each, are glowing in two separate rooms. When one of the bulbs in set A is fused, the other two bulbs also cease to glow. But in set B, when one bulb fuses, the other two bulbs continue to glow. Explain why this phenomenon occurs.
(ii) Why do we prefer arrangements of Set B for house circuiting?
Name the material which is used for making the heating element of an electric iron.
How does the presence of impurities in a metal affect its resistance?
Calculate the resistance of an aluminium cable of length 10 km and diameter 2.0 mm if the resistivity of aluminium is 27 × 10−8 Ωm.
Draw a V-I graph for a conductor at two different temperatures. What conclusion do you draw from your graph for the variation of resistance of conductor with temperature?
A graph is plotted taking p.d. along y-axis and electric current along x-axis. Name the physical quantity that represents the slope of this graph (Fig.).
To increase the effective resistance in a circuit, the resistors are connected in _______________ .
When do you say that the resistors are connected in this way? Draw a circuit diagram.
Answer the following question.
While studying the dependence of potential difference ( V) across a resistor on the current (I) passing through it, in order to determine the resistance of the resistor, a student took 5 readings for different values of current and plotted a graph between V and t. He got a straight line graph passing through the origin. What does the straight-line signify? Write the method of determining the resistance of the resister using this graph.
Two bulbs of 100 W and 40 W are connected in series. The current through the 100 W bulb is 1 A. The current through the 40 W bulb will be ______.
The voltage applied to a given rheostat is made four times its initial value. By what factor will be resistance of the rheostat change?
State expression for Resistance connected in parallel.
Illustrate-combination of cells e.g., three cells, in series, explaining the combination briefly. Obtain an expression for current ‘i’ in the combination.
The resistance of two resistors joined in series is 8Ω and in parallel is 1.5Ω. Find the value of the two resistances.
Consider the following combinations of resistors:
The combinations having equivalent resistance 1 Q is/are ______.
