Question

Task 3 a) The capacitor having a capacitance of 10 uF is applied with a potential difference which is increased uniformly from 0 to 600 V in 2 seconds. It is then maintained constant at 600 V for 1 second and subsequently decreased uniformly to zero in five seconds. 1) Plot a graph showing the variation of current during these 8 seconds. ii) Calculate the total charge and the energy stored in the capacitor when the terminal voltage is 600 V. b) A capacitor consists of two similar square Aluminium plates, each 10 cm x10 cm mounted parallel and opposite to each other. i) What is their capacitance in uF when distance between them is 1 cm and the dielectric medium is air? ii) If the capacitor is given a charge of 500 u C, what will be the potential difference between plates? iii) How will this be affected if the space between the plates is filled with wax which has a relative permittivity of ?

Answer 1

ay The capacitance of the capaciter is given as '- C= 10 uFi - CdM at and charge on the capacitor is givenas q=CV Current de The variation of relation valtage can be represented as the information provided. I= c dv dt at VA Gan 2666 socc. 8tcu aurrent Canbe represente des iTotane. I= 10x06 1600 34f 2 = 3x10² Son 18 2 3 (1112 to 3 bec. =3mA Izo -12mt n3 to 8 pce I= loxiobx 0-600 -1.2mA

(i) charge at Vzoor q=cv= 10x156x = 6.mc boo -4 =100010 =56.5 x1676 Area of the plates A=20 cm x 10cm =1000m² 20-2m2 ) capacitance of parallel plate airfilled capaciter is given as Co= AG = 102x 8.88X102 10-2 =8.88 PF Ano' Cii) Potential difference Vzq 500x106 2.85 X1612 Ciris now the capacity is filled with some dieledric of relative pormittivity = 476 New postmea permittivity of medium= Go Er New capacitance-> C= A GrGo - 4Co - New potential differences Vaq 4Co bence decreased by a factor =565x1oto 44 =4G
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