The voltage across a circuit A can be increased if resistors

The voltage across a circuit (A) can be increased if resistors are added toa circuit in series (B) can be increased if resistors are added to a circuit in parallel (C) can be decreased if resistors are added to a circuit in series (D) is neither increased nit decreased by adding resistors to a circuit. Two light bulbs are connected in a circuit. when one light bulb burns out. the other continues to give off light. These light bulbs are connected in (A) series (B) parallel (C) short circuit (D) there is not enough information to answer this question. A circuit breaker prevents the circuit from a dangerous increase in (A) current (B) voltage (C) resistance (D) none of these. When a magnet is broken into two pieces (A) one resulting piece has a south pole but no north pole, and the other has a north pole but no south pole (B) one of the resulting pieces is magnetized and the other is not (C) each resulting piece is a magnet with one north pole and one south pole (D) both resulting pieces arc demagnetized. Magne s (A) cannot be scientifically explained since their magnetic fields are not generated by a moving electrical field (B) only generate a magnetic field when they are shaken back and forth (C) are created when the spinning electrons within a material align and reinforce each other\'s magnetic fields (D) are created when the spinning electrons within a material move out of alignment and disrupt each other\'s magnetic fields. A compass is placed beside a wire. When an electric current is passed through the wire (A) the compass needle aligns with the wire\'s magnetic field (B) the company needle aligns with the earth\'s magnetic field (C) the compass needle is not affected by the current in the wire because the electric field is not moving (D) the compass needle will point to the earth\'s geographic North Pole. In particle accelerators, magnets are not used to increase the speed of electrically charged particles (though they are used to direct the path of the particles.) From your knowledge of magnets and forces, which the following statements best explains this fact? (A) magnetic forces always act parallel to the motion of a charged particle; they have a component of motion along the charged particle\'s direction of motion, and therefore cannot be used to increase the speed of a particle. (B) Magnetic forces always act perpendicular to the cotion of a charged particle; they have no component of motion along the charged particle\'s direction of motion, and therefore cannot be used to increase the speed of a particle. (C) Magnetic forces are too weak to significantly affect the motion of a charged particle. (D) Magnetic forces are so strong that they would accelerate the particles to dangerous speeds.

Solution

Using relation

i=v/R

When the resistors are connected in series, the total current decreases and and the voltage drop across each initial resistor decreases. when the resistors are added in parallel total current increases but voltage drop across ALL the resistors remains unchanged at the supply voltage. Voltage remains unchanged only when resistors are connected in parallel to the circuit.

Therefore, the correct option is c.