A non-conducting cube of side length 1m has a spherical cavity of radius 0.1m inside it. The system has a charge density of 2.5 C/m3. What is the total flux coming out of the surface of the cube?
A. 2.8*1031 Nm2C-1
B. 2.8*1011 Nm2C-1
C. 5.7*1011 Nm2C-1
D. 0.2*1011 Nm2C-1
Answer:B
A non-conducting cube of side length 1m has a spherical cavity of radius 0.1m inside it. The system has a charge density of 2.5 C/m3. What is the total flux coming out of the surface of the cube?
A. 2.8*1031 Nm2C-1 B. 2.8*1011 Nm2C-1 C. 5.7*1011 Nm2C-1 D. 0.2*1011 Nm2C-1
Explanation: The volume of material inside the cube=13–\(\frac {4\pi*0.1^3}{3}\)=0.996m3. Therefore, the total charge inside the system=volume*charge density=0.996*2.5=2.49C, Therefore the net flux coming out of the system=\(\frac {charge}{\varepsilon} = \frac {2.49}{8.85*10^{-12}}\)=2.8*1011 Nm2C-1.