(b) 1. A platinum resistance sensor has a resistance of 100 2 at 0 °C and a temperature coefficient of resistance (oc) of 4 x 10 "C. If the resistance of the sensor is 125 O, find the corresponding temperature of the sensor. ii. A variable dielectric capacitive displacement sensor consists of two square metal plates of side 5 cm, separated by a gap of 1 mm. A sheet of dielectric material 1 mm thick and of the same area as the plates can be slide between them as shown in Figure Q.4b. Given that the dielectric constant of air is 1 and that of the dielectric material is 4, calculate the capacitance of the sensor when the input displacement x-0.0 cm, 2.5 cm and 5,0 cm. Figure Q4b

A typical cell phone consumes an average of about 1.00 W ofelectrical power and operates on 3.80 V. (a) What average currentdoes the phone draw from its battery? (b) Calculate theenergy stored in a fully charged battery if the phone requirescharging after 5.00 hours of use.

When the potential difference, V, across an ohmic resistor is increased, what effect does this have on the electric current (I) and the resistance (R)?

-37 In Fig. 27-48, the resistances are R, = 2.00 N, R, = 5.00 N, and the battery is ideal. What value of R3 Ra R3 maximizes the dissipation rate in resistance 3? ww

17

(A) (in A) V Hill power (B) (in ohm) I Assume these parameter values: V = 9 volt and P = 20 W. (A) What is the electric current? (B) What is the resistance? "flashlight" schematic OA: 1.778 OB: 2.222 OC: 2.778 OD: 3.472 OE: 4.340 OF: 5.425 OG: 6.782 OH: 8.477 OA: 0.436 OB: 0.632 OC: 0.916 OD: 1.328 OE: 1.926 OF: 2.793 OG: 4.050 OH: 5.873

(6) Calculate the valui of resistors having colou bands in the following order. tù Blue, Grey Orange e, Red, Silver cii, Red, Green , Yellow, Brown, Gold, Blue

Only ans Q19

If 5 identical resistors whose resistance is R are combined in series, the equivalent resistance equals o w .......- wo R R2 Rn 1/5 R 5 R R 5+R