Nsection 12.3 it was mentioned that temperatures are often measured with electrical resistance thermometers made of platinum wire. suppose that the resistance of a platinum resistance thermometer is 125 ω when its temperature is 20.0°c. the wire is then immersed in boiling chlorine, and the resistance drops to 99.6 ω. the temperature coefficient of resistivity of platinum is α = 3.72 × 10−3(c°)−1. what is the temperature of the boiling chlorine?

- 48.55 degree

Explanation:

Resistance increases when temperature increases. This increase is linear and which is defined by the following relation between resistance and temperature

is resistance at temperature t , R₀ is resistance at temperature t₀  , t is rise in temperature and α is temperature coefficient of resistance .

Putting the values we get

125 = 99.6 ( 1 + 3.72x 10⁻³ x t )

t = 68.55

Therefore temperature of boiling chlorine is 20-68.55 = - 48.55 degree celsius .

resonant frequency

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27