Free NEET Physics Questions and Answers

Question 1

What size resistor should be placed across the 12V battery's terminals in order to generate 500mA of current?

Accepted Answer

24Ω

Answer

This problem can be solved using Ohm's Law, which states that Voltage (V) = Current (I) × Resistance (R). Given V = 12V and I = 500mA (which is 0.5 Amperes), we can rearrange the formula to find R = V / I. Therefore, R = 12V / 0.5A = 24Ω.

Question 2

What should the resistance of the heating element be if the battery is set to 24V and the total radiated power is 60W?

Accepted Answer

9.6Ω

Answer

To find the resistance, we use the power formula P = V²/R, where P is power, V is voltage, and R is resistance. Given P = 60W and V = 24V, we can rearrange the formula to solve for R: R = V²/P. Plugging in the values, R = (24V)² / 60W = 576 / 60 = 9.6Ω.

Question 3

You are required to design a circuit that has a total resistance between  40Ω and 45Ω. What resistor configuration should you use to achieve this?

Accepted Answer

R1 and R2 in parallel, connected to R3 in series

Answer

To achieve a specific total resistance within a range, a combination of series and parallel connections is often necessary. Connecting resistors in parallel reduces the overall resistance of that section, while connecting them in series adds to the total resistance. The configuration of R1 and R2 in parallel, connected to R3 in series, provides the flexibility to fine-tune the total resistance to fall within the 40Ω and 45Ω range with appropriate resistor values.

Question 4

What is the peak-to-peak AC current of 100V's RMS voltage?

Accepted Answer

35.5V

Answer

The question is ambiguously phrased, but given the correct answer, it likely asks for the RMS voltage when the peak-to-peak AC voltage is 100V. The relationship between RMS voltage (V_RMS) and peak-to-peak voltage (V_pp) is V_RMS = V_pp / (2 * √2). Therefore, V_RMS = 100V / (2 * 1.414) ≈ 100V / 2.828 ≈ 35.36V, which rounds to 35.5V.

Question 5

How can a positively charged rod make a conducting sphere on an insulating surface negatively charged?

Accepted Answer

Charge by induction

Answer

Charging by induction involves bringing a charged object near a conductor without direct contact. When a positively charged rod is brought near a conducting sphere, it attracts electrons to the near side and repels positive charges (or creates a deficit of electrons) on the far side. If the sphere is then grounded while the rod is still nearby, electrons will flow from the ground onto the sphere, leaving it with a net negative charge once the ground connection and rod are removed.

NEET - National Eligibility cum Entrance Test Practice Test

NEET - National Eligibility cum Entrance Test Practice Test

Free NEET Physics Questions and Answers