Advertisements
Advertisements
प्रश्न
What should be the length of a nickel wire of area of cross-section 3 mm2 used for making a rheostat of 750 ohm? (ρ of nickle = 0.069 Ohm mm2/m)
उत्तर
Specific resistance = ρ = 0.069 ohm `"mm"^2/"m"`
R = 750 W
A = 3mm2
as I = `("R" xx "A")/ρ = (750 xx 3)/0.069`
∴ length l = 32608.7 metre
The length of a nickel wire should be 32608.7 m.
APPEARS IN
संबंधित प्रश्न
When a 4 Ω resistor is connected across the terminals of a 12 V battery, the number of coulombs passing through the resistor per second is:
(a) 0.3
(b) 3
(c) 4
(d) 12
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.
How does the resistance of a wire change when:
its length is tripled?
What possible values of resultant resistance one can get by combining two resistances, one of value 2 ohm and the other 6 ohm?
Name the following substances:
(i) Showing low resistivity,
(ii) Showing very high resistivity,
(iii) Showing moderate resistivity.
What is the equivalent resistance between A and B in the given circuit (Fig?)
Choose the correct alternative and rewrite the following:
You are given three equal resistances. In how many combinations can they are arranged?
How does the resistance of an alloy, vary with temperature?
Four resistances of 2.0Ω each are joined end to end, to form a square ABCD. Calculate the equivalent resistance of the combination between any two adjacent comers.
Illustrate-combination of cells e.g., three cells, in parallel, explaining the combination briefly. Obtain an expression for current ‘i’ in the combination.
