Acylindrical tungsten filament 17.0cm long with a diameter of 1.20mm is to be used in a machine for which the temperature will range from room temperature (20 ? c) up to 120 ? c. it will carry a current of 12.5a at all temperatures ( resistivity of tungsten at 20 ? c is 5.25�10? 8? ? m , the temperature coefficient of resistivity at 20 ? c is 0.0045 ? c? 1 )

a) what will be the maximum electric field in this filament?

express your answer using two significant figures.

b) what will be its resistance with that field?

express your answer using two significant figures.

c) what will be the maximum potential drop over the full length of the filament?

express your answer using two significant figures.

Explanation:

R = ρ L / S

ρ is resistivity , L is length of wire and S is cross sectional area

R at 20 degree

=

R₁ = 78.95 x 10⁻⁴ Ω

Resistivity at 120 degree

= 5.25 x 10⁻⁸ ( 1 + 5.25 x 10⁻⁸ x .0045 x 100)

= 7.61 x 10⁻⁸

Resistance at 120 degree

=

R₂= 114.44 x 10⁻⁴ Ω

Potential difference at 20 degree

= current x resistance

= 12.5 x 78.95 x 10⁻⁴

= 986.875 x 10⁻⁴ V

Electric field at 20 degree

= Potential diff / length

= 986.875 x 10⁻⁴ / 17 x 10⁻²

= 58 x 10⁻² V/m

Potential difference at 120 degree

= current x resistance

= 12.5 x 114.44 x 10⁻⁴

= 1430.5  x 10⁻⁴ V

Electric field at 120 degree

= Potential diff / length

= 1430.5 x 10⁻⁴ / 17 x 10⁻²

= 84.15  x 10⁻² V/m

A ) Maximum electric field = 84.15  x 10⁻² V/m

B )  114.44 x 10⁻⁴  Ω

C ) 1430.5  x 10⁻⁴ V

a.   mass number from atomic number

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.