Physics Past Paper PDF

If two resistors with resistances of 10 Ω and 20 Ω are connected in series to a 30 V battery, and then connected in parallel to the same battery, which of the following statements is true about the total current in the circuit? A. The total current in the series circuit will be greater than in...

If two resistors with resistances of 10 Ω and 20 Ω are connected in series to a 30 V battery, and then connected in parallel to the same battery, which of the following statements is true about the total current in the circuit? A. The total current in the series circuit will be greater than in the parallel circuit. B. The total current in the series circuit will be the same as in the parallel circuit. C. The total current in the parallel circuit will be greater than in the series circuit. D. The total current in both circuits will be zero. When an object becomes charged by rubbing, what causes the charge transfer to occur? A. Protons moving between objects B. Neutrons moving between objects C. Electrons transferring from one object to another D. The objects sharing their charges equally Which of the following best describes Kirchhoff's Current Law (KCL)? A. The sum of the potential differences around any closed loop is zero. B. The total current entering a junction is equal to the total current leaving the junction. C. The total resistance in a parallel circuit is equal to the sum of the individual resistances. D. The total power dissipated in a circuit is equal to the product of the total current and total voltage. Which of the following best describes charging by induction? A. Transferring charge by directly touching another object B. Charging an object by rubbing it with another material C. Rearranging the charges in an object without direct contact D. Destroying charges by bringing an object near a neutral body A wire's resistance is 8 Ω. If the length of the wire is doubled while the cross-sectional area is halved, how will the new resistance compare to the original resistance? A. The new resistance will be 16 Ω. B. The new resistance will be 4 Ω. C. The new resistance will be 32 Ω. D. The new resistance will be 64 Ω. What is the key difference between charging by rubbing and charging by induction? A. Rubbing involves contact, while induction does not require direct contact B. Induction transfers protons while rubbing transfers neutrons C. Rubbing creates charges, while induction destroys charges D. Induction involves rubbing objects together to generate heat If the length of a wire is halved and its cross-sectional area is doubled, how will the resistance of the wire change according to the relationship R=ρ L/A​? A. The resistance will remain the same. B. The resistance will double. C. The resistance will be halved. D. The resistance will be reduced by a factor of 4. What principle calculates the net electric field at a point due to multiple charges? A. Coulomb's law and the principle of charge conservation B. The superposition principle, summing vector contributions from each charge C. Gauss's law applied to point charges D. Subtracting the weaker charge field from the stronger one According to the formula R=ρ L/A​, which of the following statements is correct regarding the relationship between resistance, length, and cross- sectional area of a wire? A. The resistance of a wire increases as its length decreases. B. The resistance of a wire decreases as its cross- sectional area increases. C. The resistance of a wire increases as its cross- sectional area increases. D. The resistance of a wire is independent of its Two charges, q1=+2 C and q2=−3 C are placed 4 m apart. What is the correct approach to calculate the electric field at a point midway between them? A. Use Coulomb’s law to calculate the field due to each charge and then add the magnitudes of the fields directly. B. Use Coulomb’s law to find the field vectors due to each charge and add them using vector addition. C. Find the net charge and use Coulomb’s law to calculate the total field. D. Ignore the charges since the point is equidistant from both. If the length of a wire is doubled and its cross- sectional area is halved, how will the resistance of the wire change according to the formula for resistance R=ρ L/A​, where ρ is the resistivity, L is the length, A is the cross-sectional area? A. The resistance will remain the same. B. The resistance will double. C. The resistance will quadruple. D. The resistance will increase by a factor of 4. A charge of an atom, q=+4 C is placed 6 m apart along a straight line. What is the magnitude of the net electric field​? A. 9.99 x 108 N/C B. 9.0 x 108 N/C C. 9 x 108 N/C D. 10 x 108 N/C A light bulb has a resistance of 12 Ω. When connected to a 24 V power supply, what is the current flowing through the light bulb according to Ohm's law? A. 1 A B. 2 A C. 12 A D. 24 A Find the electrostatic force between charges of +5.0 C and +3.0 C separated by a distance of 75 m in a vacuum. A. 3.2 x 107 N B. 2.7 x 107 N C. 1.8 x 107 N D. 2.4 x 107 N In an electrical circuit with a resistor made of Ohmic material, the resistance is 10 Ω, and the voltage across the resistor is 20 V. Using Ohm's law, what is the current flowing through the resistor? A. 0.5 A B. 2 A C. 20 A D. 200 A Two charges of +8.0 C and -6.0 C attract each other with a force of 3.0 x 103 N in a vacuum. What is the distance between the charges? A. 4.3 x 107 m B. 1.6 x 107 m C. 1.2 x 107 m D. 3.5 x x 107 m Which of the following best describes the relationship between current, voltage, and resistance in Ohmic materials, according to Ohm's law? A. The current is directly proportional to the voltage and inversely proportional to the resistance. B. The current is inversely proportional to both the voltage and the resistance. C. The voltage is directly proportional to the resistance and inversely proportional to the current. D. The voltage is directly proportional to the current and inversely proportional to the resistance. You are designing an electronic device with a sensor that operates based on electric fields. Two small charged objects, q1=+5 μC, and q2=−3 μC, are placed 4 m apart on a straight line to create an electric field for the sensor. The sensor is located at a point, which is 2 m from q1​and 2 m from q2​. What is the net electric field experienced by the sensor at this point? A) 5×104 N/C B) 4 × 104 N/C C) 1.8×104 N/C D) 2 × 104 N/C A current of 0.25 A flows through a conductor for 2 hours, and the same current flows through another conductor for 5 hours. Which conductor experiences a greater total charge transfer? A. The conductor with 0.25 A for 2 hours transfers more charge. B. The conductor with 0.25 A for 5 hours transfers more charge. C. Both conductors transfer the same amount of charge. D. The conductor with 0.25 A for 2 hours transfers at no charge. A charge q0=+1 μC is placed at the origin of a coordinate system. Two other charges, q1=+2 μC and q2=−3 μC are located at points (2 m, 0) and (0,3 m), respectively. Which of the following steps is incorrect in determining the net force on q0 due to q1 and q2​? A) Calculate the force due to q1​on q0​using Coulomb's law. B) Calculate the force due to q2​on q0​using Coulomb's law. C) Add the magnitudes of the forces due to q1​and q2​ directly without considering their directions. D) Use vector addition (Pythagorean theorem) to calculate the net force on q0​by combining the x and y components of the forces. A current of 4 A flows through a conductor for 10 minutes. If the conductor is replaced and the current is reduced to 2 A, but the time is increased to 30 minutes, which situation results in a greater total charge transferred? A. The situation with 4 A current for 10 minutes transfers more charge. B. The situation with 2 A current for 30 minutes transfers more charge. C. Both situations transfer the same charge. D. The situation with 4 A current for 10 minutes transfers less charge. Two point charges, +4 μC and −6 μC are placed 8 m apart. A third charge, +2 μC is located 3 m away from q1 and 5 m away from q2​. What can be said about the direction of the net force on q3​? A) The net force on q3 points toward q1​. B) The net force on q3​points toward q2. C) The net force on q3​points somewhere between q1​and q2, depending on their relative force magnitudes. D) The net force on q3​is zero because the charges cancel each other. A battery is connected to a resistor and a current of 0.5 A flows for 20 minutes. After 10 minutes, the current is increased to 1.0 A. What is the total charge transferred during these 20 minutes? A) 10 C B) 12 C C) 15 C D) 20 C When two charges exert forces simultaneously on a third charge, the total force acting on that charge is the vector sum of the forces that the two charges would exert individually. This principle is known as the _____. A. interference of charge B. Coulomb’s principle C. superposition of forces D. superposition of electric field A current of 2 A flows through a conductor for 3 minutes. If the current is maintained for an additional 2 minutes, what will happen to the total charge transferred during these 5 minutes? A. The total charge transferred will increase to 10 C. B. The total charge transferred will increase to 12 C. The total charge transferred will decrease to 8 C. D. The total charge transferred will remain at 6 C. Two charged objects attract each other with a certain force. If the charges on both objects are doubled with no change in separation, what will happen to the force between them? A. quadruples B. doubles C. halves D. increases If the current in a circuit is doubled while keeping the time constant, what will happen to the total charge transferred according to the equation Q= I × t? A. The total charge will remain the same. B. The total charge will be halved. C. The total charge will double. D. The total charge will be quadrupled. An air purifier uses an electric field to trap dust particles by charging them as they pass through a region with a uniform electric field. If the dust particles are modeled as tiny charged spheres and a Gaussian surface is imagined around one of these particles, which of the following statements is correct about the electric flux through the Gaussian surface? A. The electric flux depends on the electric field strength generated by the air purifier. B. The electric flux depends only on the charge of the dust particle enclosed by the Gaussian surface. C. The electric flux depends on the radius of the Gaussian surface around the dust particle. D. The electric flux is zero because the charge is small. If the current in a circuit is constant and flows for a longer period, what happens to the total charge transferred according to the equation Q=I × t? A. The total charge increases because the charge is directly proportional to time. B. The total charge decreases because the charge is inversely proportional to time. C. The total charge remains the same regardless of the time. D. The total charge increases because the charge is inversely proportional to time. In photocopiers, a uniform electric field is used to distribute toner particles on a charged drum. If a toner particle carries a charge q=−5 μC, which of the following statements best describes the electric flux through a Gaussian surface surrounding the toner particle? A. The electric flux depends on the total electric field created by the drum and the toner particle. B. The electric flux is negative because the toner particle has a negative charge. C. The electric flux depends on the size of the Gaussian surface around the toner particle. D. The electric flux is positive because the drum creates a uniform electric field. If the current in a circuit is 3 A and it flows for 5 seconds, what is the total charge transferred during this time according to the equation Q=I × t? A) 15 C B) 8 C C) 3 C D) 5 C An electric field of 6 N/C on a flat surface with an area of 4 m2 is placed in the field. The surface is oriented at different angles for the electric field, and the electric flux through the surface is calculated for each angle. Which of the following statements is true about the electric flux through the surface? A. The electric flux is maximum when the surface is oriented parallel to the electric field. B. The electric flux is zero when the surface is perpendicular to the electric field. C. The electric flux is the same for any orientation of the surface. D. The electric flux is minimal when the surface is oriented parallel to the electric field. What does the equation Q=I × t represent in terms of electric current? A. The total amount of charge passing through a conductor in a given time. B. The energy required to move a charge through a conductor. C. The force experienced by a charge in a conductor. D. The voltage required to move a certain amount of charge through a conductor. A spherical surface of r=5 m surrounds a point charge q=+2 μC. If the radius of the spherical surface is doubled to r=10, how does the electric flux through the surface change? A. The electric flux doubles because the surface area increases. B. The electric flux is halved because the radius increases. C. The electric flux remains the same because it depends only on the enclosed charge. D. The electric flux increases by a factor of four because the radius increases. A capacitor with a capacitance 5 μF is charged to a voltage of 10 V, storing a charge of 50 µC. Suppose the capacitor is connected to a battery that maintains a constant voltage of 10 V, and a dielectric with a dielectric constant of 2 is inserted. What will happen to the charge, capacitance, and voltage across the plates? A. The capacitance increases to 10 µF, the charge remains the same, and the voltage decreases to 5 V. B. The capacitance increases to 10 µF, the charge increases to 100 µC, and the voltage remains at 10 V. C. The capacitance remains the same, the charge remains at 50 µC, and the voltage remains at 10 V. D. The capacitance increases to 10 µF, the charge remains at 50 µC, and the voltage remains at 10 V. Which of the following factors does not affect the strength of the electric field created by a point charge? A. The magnitude of the charge. B. The distance from the charge. C. The presence of other charges nearby. D. The medium (material) surrounding the charge. A capacitor with a capacitance of 10 µF is charged to 6 V, storing a charge of 60 µC. Suppose a dielectric with a dielectric constant of 4 is inserted while the capacitor is disconnected from the power supply. What will happen to the charge, capacitance, and voltage across the plates? A. The capacitance increases to 40 µF, the charge remains the same at 60 µC, and the voltage decreases to 1.5 V. B. The capacitance increases to 40 µF, the charge increases to 240 µC, and the voltage remains the same at 6 V. C. The capacitance increases to 40 µF, the charge remains the same at 60 µC, and the voltage remains the same at 6 V. D. The capacitance remains at 10 µF, the charge remains the same at 60 µC, and the voltage increases to 24 V. Which of the following correctly describes how the strength of the electric field changes when the distance from a point charge is doubled? A. The electric field strength doubles. B. The electric field strength is halved. C. The electric field strength is reduced by a factor of four. D. The electric field strength remains unchanged. Which of the following is a correct statement about the direction of the electric field created by a positive point charge? A. The electric field points radially inward toward the charge. B. The electric field points radially outward from the charge. C. The electric field is tangent to the surface of a sphere surrounding the charge. D. The electric field is parallel to the line connecting two positive charges. What happens when a dielectric material is inserted between the plates of a charged capacitor? A. The capacitance increases, the charge on the plates decreases, and the electric field remains the same. B. The capacitance increases, the charge on the plates remains the same, and the electric field decreases. C. The capacitance decreases, the charge on the plates remains the same, and the electric field increases. D. The capacitance decreases, the charge on the plates increases, and the electric field decreases. Which of the following best describes the nature of the electric field between two parallel plates connected to a battery? A. The electric field is uniform and points from the positive plate to the negative plate. B. The electric field is radial and points away from the positive plate. C. The electric field is non-uniform and points from the negative plate to the positive plate. D. The electric field is zero between the plates. In a camera’s flash unit, capacitors are used to store energy. Why are capacitors the preferred choice in this application? A. Capacitors can release the stored energy quickly to generate a high-intensity flash. B. Capacitors allow energy to be stored for a long time, ensuring the flash is ready whenever needed. C. Capacitors regulate power consumption to reduce energy usage. D. Capacitors amplify the energy to create a stronger flash. Which of the following best describes the electric potential at a point due to a positive point charge? A. The electric potential is always negative at all points. B. The electric potential decreases as the distance from the charge increases. C. The electric potential increases as the distance from the charge increases. D. The electric potential is constant and independent of the distance from the charge. Why are capacitors important in signal processing applications, such as in audio systems or radio receivers? A. They prevent the loss of signal strength by amplifying weak signals. B. They filter out unwanted frequencies, allowing only the desired signal to pass. C. They act as resistors to control the current flow in the circuit. D. They store energy and release it to keep the signal at a constant level. What is the electric potential at a point halfway between two equal and opposite charges +Q and −Q, separated by a distance? A. The electric potential is zero. B. The electric potential is positive. C. The electric potential is negative. D. The electric potential is infinite. How do capacitors contribute to the functioning of a filtering circuit in electronics? A. Capacitors allow high-frequency signals to pass through while blocking low-frequency signals. B. Capacitors store high-frequency signals and prevent them from entering the circuit. C. Capacitors smooth out fluctuations in voltage by storing and releasing charge. D. Capacitors store power and release it only when the circuit is turned off. Why are capacitors used in timing circuits, such as those in oscillators or clocks? A. To control the rate at which the circuit charges and discharges, determining the timing cycle. B. To reduce the power consumption of the circuit. C. To store magnetic energy for short bursts of power. D. To increase the voltage of the circuit over time. If the distance between two charges is doubled, how does the electric potential energy of the system change? A. The electric potential energy is doubled. B. The electric potential energy is halved. C. The electric potential energy is reduced by a factor of four. D. The electric potential energy remains unchanged. Why are capacitors used in power supply circuits in electronic devices? A. To store and release electrical energy to smooth out fluctuations in voltage. B. To increase the total resistance in the circuit. C. To convert AC into DC. D. To store and discharge magnetic energy.