1.1. Thin films of carbon are sometimes used in electronic systems. 

Typical dimensions of such a film are shown in Figure 1: 

Figure 1

Calculate the current which passes through the carbon film in Figure 1 for an applied voltage of 2.5 mV. 

The resistivity of carbon = 4.0 × 10^–5 Ω m

1.2. The applied voltage is kept constant, but the current is now directed through the carbon film as shown in Figure 2: 

Figure 2

Show that the current is 6 orders of magnitude larger if it is directed through the carbon film as shown in Figure 2. 

1.3. A tensile force is applied to the carbon film as shown in Figure 2, in a plane that is normal to the current. 

Without performing any calculations, predict how the resistance of the carbon film changes as a result of the applied tensile force.  Justify your reasoning and state any assumptions you make.