a)If your torsion balance deflects to an angle of 10° when your two spheres are 40cm apart, what angle will it deflect to when the spheres are 10cm apart?

b)If your torsion balance deflects to an angle of 10° when your two spheres are 20cm apart, and charged to a potential of 8 kV, what angle will it deflect to when the spheres are charged to a voltage of 4kV?

Respuesta :

Answer:

Explanation:

Given

for [tex]\theta=10^{\circ}[/tex]

Sphere are [tex]d=40\ cm[/tex]

when sphere [tex]d_2=10\ cm[/tex] apart suppose deflection is [tex]\theta _2[/tex]

We know

[tex]F=k_t\cdot \theta [/tex]

Where F=force between charged particle

[tex]\theta =[/tex]Deflection

[tex]F=\frac{kQ_1Q_2}{r^2}=k_t\cdot \theta [/tex]

[tex]\theta =\frac{k}{k_t}\times \frac{Q_1Q_2}{r^2}----1[/tex]

thus [tex]\theta \propto \frac{1}{r^2}[/tex]

for [tex]\theta _2[/tex]

[tex]\frac{\theta _1}{\theta _2}=(\frac{r_2}{r_1})^2[/tex]

[tex]\theta _2=16\times \theta _1[/tex]

[tex]\theta _2=160^{\circ}[/tex]

(b)for [tex]10^{\circ}[/tex] deflection Potential [tex]v_1=8\ kV[/tex]

Electric Potential is [tex]V=\frac{kQ}{r}[/tex]

[tex]Q=\frac{V\cdot r}{k}[/tex]

where V=voltage

k=constant

r=distance between charges

Put value of Q in equation 1

[tex]\theta =\frac{k}{k_t}\times \frac{V^2r^2}{k^2}[/tex]

[tex]\theta =\frac{V^2r^2}{k\cdot k_t}[/tex]

thus [tex]\theta \propto V^2[/tex]

therefore

[tex]\frac{\theta _1}{\theta _2}=(\frac{V_1}{V_2})^2[/tex]

[tex]\frac{10}{\theta _2}=(\frac{8}{4})^2[/tex]

[tex]\theta _2=\frac{10}{4}=2.5^{\circ}[/tex]