Electrical Engineering Answers

A coil has a length of 3m having an electron density of 3.34 x 1024 e/m3 with a cross sectional area of 100 cm squared. How much current will pass through the conductor in 1hr?

 An electron gun in a TV set shoots out a beam of electrons. The beam current is 2.1µA. How many electrons strike the TV screen for 5 seconds? How much charge strikes the screen in a minute?

Determine the resistance and the power absorbed by an electric heater that uses 5.0 A when connected across 110 V.

How much charge flow through a light bulb for 3 seconds if the current through the light bulb is 0.75 A?

The current in an electric lamp is 5 A. What quantity of electricity flows towards the filament in 6 minutes?

Consider a message signal 𝑚(𝑡) with bandwidth 𝑊 = 2 𝑘𝐻𝑧 , applied to a DSB-SC modulator, s.t., 𝑠(𝑡) = 𝐴𝑐𝑚(𝑡) cos(2𝜋𝑓𝑐 𝑡). Assuming perfect synchronism between the carrier waves in the modulator and detector. a. Determine (sketch) the spectrum of the detector output when 𝑓𝑐 = 1 𝑘𝐻𝑧. (Note: 𝑀(𝑓) is shown in the figure, and 𝑀(0) = 1.) b. Find the lowest 𝑓𝑐 for which each component of the modulated wave 𝑠(𝑡) is uniquely determined by 𝑚(𝑡). Sketch the spectrum of the detector output with the lowest 𝑓𝑐 that you have required. 

The average value of an oscillating electric current over one period may be zero. For example, 2nt suppose that the current is described by a simple sinusoid: i(t) = sin 2πt/T where T is the period.

The average value of this function can be determined by the following equation:

i=∫ν0^T(2πt/T)dt/T-0 = -cos(2π) + cos0/T=0

Despite the fact that the net result is zero, such current is capable of performing work and generating heat . Therefore, electrical engineers often characterize such current by

I RMS = √1\T∫ν0^Ti^2(t)dt

where i(t) = the instantaneous current. Calculate the RMS or root-mean-square current of the waveform shown in following figure using the trapezoidal rule, Simpson's 1/3 rule, Simpson's 3/8 rule for T =1 s taking n = 6.

A parallel plate capacitor is made of 250 plates separated by a

dielectric 0.0012cm thick. The effectíve size of thé plate is 12cm x

24cm. If the dielectric constant is 2.5, what is the capacitance of

this capacitor?

Each electrode of a capacitor of the electrolytic type has an area o

0.02㎡,The relative permittivity of the dielectric aim is 2.8. if the

capacitor has a capacitance of 10uf, estimate the thickness of the

dielectric film. 

A parallel-plate capacitor, having plates of 100c㎡ and has three

dielectrics 1mm each and of permittivity’s 3, 4 and 6. If the peak

voltage 2000V is applied to the plates, calculate the energy stored

in each dielectric