Two capacitors of capacitance 2 μF 1μF are connected in parallel. A p.d of 3V is applied across them. Find the energy stored in the combination. (2mks)
0 Comments
K.C.S.E Physics Q & A - MODEL 2017PP2QN18
​(a) State two factors that affect the capacitance of a parallel plate capacitor.
(b) Figure 9 shows an electric circuit in which three capacitors are connected across a power supply. 
​Determine the;
(i) total capacitance, (ii) quantity of charge stored on the 8uF capacitor.
answers
​(a) — Area of overlap of the plates
— Distance between the plates. — Type of dielectric. 
K.C.S.E Physics Q & A - MODEL 2017PP2QN14
State how heating is achieved in a resistance wire.
answer
K.C.S.E Physics Q & A - MODEL 2017PP2QN13
​Figure 4 shows three resistors connected in series.
​Using Ohm’s law, show that the effective resistance is given by the expression:
RT=RI+R2+R3
answer
K.C.S.E Physics Q & A - MODEL 2016PP2QN16
​Figure 8, shows a circuit that may be used to charge a capacitor.
(i) state the observation on the milliameter when the circuit is switched on:
(ii) explain the observation in (i) above. b)The circuit in figure 8 is left on for some time. State the value of p.d. across: (i) the resistor R; (ii) the capacitor C; (c) sketch the graph of potential difference (V) across R against time. ​(d) Figure 9 shows three capacitors connected to a 10V battery 
​Calculate:
(i) the combined capacitance of the three capacitors; (ii) the charge on the 5.0 uF capacitor.
answers
​(a)(i)Current falls off to zero.Falling to zero deflects to maximum then zero.
(ii)Current flows when the capacitor is charging. When fully charged no current flows and potential difference (p.d.) is equal to charging voltage (b) (i)VR = 0 volts (ii)Vc = 5 Volts 
K.C.S.E Physics Q & A - MODEL 2015PP2QN17
​(a) State three factors that affect the capacitance of a parallel plate capacitor.
(b) Figure 5 shows the circuit used to charge a capacitor C 
​(i) State what would be observed on the following when the switch is closed:
(I) the milliammeter; (II) the voltmeter; (ii) Explain how the capacitor gets charged. (iii) State the purpose of the resistor R. (iv) On the axes provided, sketch the graph of voltage (V) against time (t) 
answers
​(a) distance of separation between plates
area of overlap of plates type of dielectric between plates (b) (i) (I) Current rises to maximum and then drops to zero (II) Potential difference between the plates increases to a maximum (ii) Negative charges flow from the negative terminal of the battery to one plate of the capacitor. Negative charges flow from the other plate of the capacitor to the positive terminal of the cell hence equal positive and negative charges gather on the plates, opposing further flow of electrons when fullycharged (iii) Resistor - to slow down the charging process so that current and voltage are is observed. 
K.C.S.E Physics Q & A - MODEL 2014PP2QN02
State the effect of decreasing the distance between the plates of a parallel plate capacitor on the capacitance.
answer
K.C.S.E Physics Q & A - MODEL 2013PP2QN15
​(a) Explain how a positively charged electroscope gets discharged when the cap is touched with a finger.
(b) Figure 7 shows capacitors A and B connected in series with a battery of e .m .f 4 V. 
​Determine:
(ï) the effective capacitance of the circuit. (ii) the quantity of charge in capacitor A. (iii) the quantity of charge in capacitor B. (c) Figure 8 shows an isolated negative point charge Q. 
​On the figure. sketch the electric field pattern around the charge.
answers
​(a) Negative charges flow from earth to cap.
Negative charge neutralizes the positive. 
K.C.S.E Physics Q & A - MODEL 2011PP2QN11
​A 4 ohms resistor is connected in series to a battery of e.m.f 6V and negligible internal resistance. Determine the power dissipated by the resistor.
answer
K.C.S.E Physics Q & A - MODEL 2011PP2QN03
​Figure 3, shows a voltmeter connected across two charged parallel plates.
​When a thin sheet of mica is inserted between the plates, the voltmeter reading is observed to reduce. Explain this observation.
answer
K.C.S.E Physics Q & A - MODEL 2010PP2QN15
​(a) Figure 8, shows a circuit that may be used to charge a capacitor.
​(i) state the observation on the milliameter when the circuit is switched on:
(ii) explain the observation in (î) above. (b) The circuit in figure 8 is left on for some time. State the value of p.d. across: (j) the resistor R; (ii) the capacitor C; (c) sketch the graph of potential difference (V) across R against time. (d) Figure 9 shows three capacitors connected to a 10V battery. 
Calculate:
(î) the combined capacitance of the three capacitors; (ii) the charge on the 5.0 uF capacitor.
answers
(a) (1) High current which falls off to zero.
(ii) Current flows when the capacitor is charging. When fully charged current stop (no current) and p.d. is equal to charging voltage. 
K.C.S.E Physics Q & A - MODEL 2010PP2QN10
A current I flowing through a wire of resistance R was increased seven times. Determine the factor by which the rate of heat production was increased.
answer
K.C.S.E Physics Q & A - MODEL 2009PP2QN14
​ (a) Figure 7 shows a pair of parallel plates of a capacitor connected to a Battery the upper plates is displaced slightly to the left.
​State with reason the effect of this movement of the capacitance
(b) Figure 8 shows an electrical circuit with three capacitors A, B and C of capacitance 4.0 μF, 5.0 μF and 3.0 μF respectively connected to a 12V battery 
Determine:
(i) The combined capacitance of the three capacitors (ii) The charge of the capacitor A (iii) The potential difference across the capacitors B
answers
K.C.S.E Physics Q & A - MODEL 2007PP2QN09
​A heater of resistance R1 is rated P watts, V volts while another of resistance R2 is rated 2P watts, V/2 volts. Determine R1 / R2
ANSWER
K.C.S.E Physics Q & A - MODEL 2005PP2QN03
3 When the switch is closed determine the:
(i) Ammeter reading (ii) Charge on each conductor
answers
K.C.S.E Physics Q & A - MODEL 2005PP1QN19
A hair drier is rated 2500W, 240V. Determine its resistance.
answer
K.C.S.E Physics Q & A - MODEL 2004PP1QN26
​The capacitors in the circuit in fig 14 are identical and initially uncharged.
Switch S1 is closed while switch s2 remains open. After sometime, switch s1 is opened and switch s2 closed. Determine the final reading of the voltmeter, V
answer
K.C.S.E Physics Q & A - MODEL 2003PP1QN37
​ Figure 20 shows three capacitors connected between two points A and B.
Determine the capacitance across AB
ANSWER
K.C.S.E Physics Q & A - MODEL 2002PP1QN21
​Fig. 11 shows part of the circuit containing tow capacitors of 2 uF and 3uF respectively.
​Determine the p.d across AB given that the total charge in the capacitors is 1x10-4 Coulombs.
answer
K.C.S.E Physics Q & A - MODEL 2000PP1QN26
​ Fig. 15 shows a battery of emf 3.0 V connected in series with two capacitors.
ANSWER
K.C.S.E Physics Q & A - MODEL 1997PP1QN28
Figure 11 shows part of a circuit containing three capacitors
Write an expression for CT the effective capacitance between A and B
ANSWERS
K.C.S.E Physics Q & A - MODEL 1996PP1QN25
In some petrol engines where spark plugs are used, a capacitor is connected to the distributor. Suggest the function of the capacitor.
ANSWERS
|
CATEGORIES
Categories
All
Topics
FORM I - PHYSICS SYLLABUSFORM II - PHYSICS SYLLABUSTOPICS
FORM III - PHYSICS SYLLABUSFORM IV - PHYSICS SYLLABUSARCHIVES
RSS FEEDS
AUTHOR
M.A NyamotiMy passion is to see students pass using right methods and locally available resources. My emphasis is STEM courses
|
RSS Feed