Advertisements
Advertisements
प्रश्न
A wire of resistance 9 ohm having length 30 cm is tripled on itself. What is its new resistance?
Advertisements
उत्तर
Resistance (R) = 9 ohm
Length l = 30 cm
New Length (l) = 30 cm = `l/3` = 10 cm
New area an = 3a
`R = ρ 1/a`
Initial resistance `9 = ρ 30/a` ...(i)
New resistance `R_n = ρ 10/(3a)` ...(ii)
On dividing eqn (ii) by (i), we get,
`R_n/9 = (ρ 10/(3a))/(ρ 30/a)`
`R_n /9 = 10/90`
`R_n /9 = 1/9`
`R_n /1 = 9/9`
Rn = 1 Ω
Hence, The new resistance = 1 ohm.
APPEARS IN
संबंधित प्रश्न
The relationship between the potential difference and the current in a conductor is stated in the form of a law.
1) Name the law.
2) What does the slope of V-I graph for a conductor represent?
3) Name the material used for making the connecting wire.
Name the unit of electrical resistance and give its symbol.
Name the physical quantity whose unit is "ohm".
What is the necessary condition for a conductor to obey Ohm’s law?
Which of the following is an ohmic resistance?
A wire of resistance 3 ohm and length 10 cm is stretched to length 30 cm. Assuming that it has a uniform cross section, what will be its new resistance?
Define the following:
Coulomb
A heater of 220 V heats a volume of water m 5 mint time. A heater of 110 V heat in ten second. The resistance of the conductor is
A metal rod of length 10 cm and a rectangular cross-section of 1 cm × `1/2` cm is connected to a battery across opposite faces. The resistance will be ______.
The circuit depicted in the figure is employed for studying Ohm’s Law. Instead of using a standard resistor, a student opts for a glass tube filled with mercury (tube 1), connected to the circuit through two electrodes, E1 and E2. He records the readings of the ammeter and voltmeter, thereby calculating the resistance. The student repeats the experiment by substituting tube 1 with tube 2, where the same amount of mercury fills tube 2.
Neglecting internal resistance of the cell use (> or < or =) to compare:
- the resistance in both the cases.
- the voltmeter readings in both the cases.
- the specific resistance in both the cases.
