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NEET - Grade 12 - Physics - Current Electricity - Introduction and Snapshot of Current Electricity - Study ref# 812

Introduction: In Chapter 1, all charges whether free or bound, were considered to be at rest. Charges in motion constitute an electric current. Such currents occur naturally in many situations. Lightning is one such phenomenon in which... read more

NEET - Grade 12 - Physics - Current Electricity - Introduction and Snapshot of Current Electricity - Study ref# 813

Following sections must be covered to understand the Current Electricity: 1. Introduction 2. Electric Current 3. Electric Currents in Conductors 4. Ohm’s law 5. Drift of Electrons and the Origin of Resistivity 6. Limitation... read more

NEET - Grade 12 - Physics - Current Electricity - Target Setup for Current Electricity - Study ref# 814

Student requires to achieve the following milestones to get better grip over Current Electricity. The milestones / targets are as follows: Starting Point: Days 0Test TypeAppear on TestTarget TestsScorePractice Test000%Chapter Tes... read more

NEET - Grade 12 - Physics - Electromagnetic Induction - Introduction and Snapshot of Electromagnetic Induction - Study ref# 821

Introduction: Electricity and magnetism were considered separate and unrelated phenomena for a long time. In the early decades of the nineteenth century, experiments on electric current by Oersted, Ampere and a few others established t... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10490

The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4 , what is the maximum current that can be drawn from the battery? Hints – To find the maximum current, use the concept that the current... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10491

(a) Three resistors 2?, 4? and 5? are combined in parallel. What is the total resistance of the combination? (b) If the combination is connected to a battery of emf 20 V and negligible internal resistance, determine the currently through ... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10492

At room temperature (27.0℃) the resistance of a heating element is 100Ω. What is the temperature of the element, if the resistance is found to be 117Ω, given that the temperature given that the temperature coefficient of the ... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10493

A negligible small current is passed through a wire of length 15 m and uniform cross-section  m2 and its resistance is measured to be 5.0 Ω. What is the resistivity of the material at the temperature of the experiment? Answer: Given, ... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10494

Determine the current in each branch of the network shown in given figure. Hints – Here, the given circuit is closed having two closed loops, so to calculate the current in the circuit we have to apply Kirchhoff’s laws. Answer: From Kirch... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10495

A storage battery of emf 8.0 V and internal resistance 0.5 ? is being charged by a 120 V DC supply using a series resistor of 15.5?. What is the terminal voltage of the battery during charging? What is the purpose of having a series resistor... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10496

In a potentiometer arrangement, a cell of emf 1.25 V gives a balance point at 35.0 cm length of the wire. If the cell is replaced by another cell and the balance point shifts to 63.0 cm, what is the emf of the second cell? Hints – Use the... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10497

The number density of free electrons in a copper conductor estimated at  . How long does an electron take to drift from one end of a wire 3.0 m long to its other end? The area of cross-section of the wire is  and it is carrying a current ... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10498

The earth’s surface has a negative surface charge density of  The potential difference of 400kV between the top of the atmosphere and the surface results (due to the low conductivity of the lower atmosphere) in a current of only 1800 A ov... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10499

Two wires of equal lengths, one of aluminum and the other of copper have the same resistance. Which of the two wires is lighter? Hence, explain why aluminum wires are preferred for overhead power cables? read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10500

Answer the following question: A steady current flows in a metallic conductor of non-uniform cross-section. Which of these quantities is constant along the conductor: current, current density, electric field and drift speed? Answer:... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10501

Answer the following question: Is Ohm’s law universally applicable for all conducting elements? If not, give examples of elements which do not obey Ohm’s law. Answer: No, Ohm’s law is not applicable for all conducting elements. Vacuum ... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10502

Answer the following question: A low voltage supply from which one needs high currents must have very low internal resistance. Why? Answer: For very high current, the internal resistance should be low by according to the formula read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10503

Answer the following question: A High Tension (HT) supply of (say) 6 kV must have a very large internal resistance. Why? Answer: A high tension supply must have a very large internal resistance because if the circuit is shorted the intern... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10504

Figure shows a potentiometer with a cell of 2.0 V and internal resistance 0.40 ? maintaining a potential drop across the resistor wire AB. A standard cell which maintains a constant emf of 1.02 V (for very moderate currents upto a few mA) gi... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10505

The relaxation time  is nearly independent of applied E field whereas it changes significantly with temperature T, first fact is (in part) responsible for Ohm’s law whereas the second fact leads to variation of P with temperature. Elaborate ... read more

NEET - Grade 12 - Physics - Current Electricity - Study ref# 10506

AB is a potentiometer wire (see figure). If the value of R is increased, in which direction will the balance point J shift? Answer: As the value of R increased, the current flowing in the circuit will decrease. And the potential gradient i.e... read more

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