Please select a subject first
Advertisements
Advertisements
A heating element using nichrome connected to a 230 V supply draws an initial current of 3.2 A which settles after a few seconds to a steady value of 2.8 A. What is the steady temperature of the heating element if the room temperature is 27.0°C? The temperature coefficient of resistance of nichrome averaged over the temperature range involved is 1.70 × 10−4 °C−1.
Concept: Temperature Dependence of Resistance
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?
Concept: Cells, Emf, Internal Resistance
How does drift velocity of electrons in a metallic conductor vary with increase in temperature? Explain.
Concept: Drift of Electrons and the Origin of Resistivity
A charge Q is distributed uniformly over a metallic sphere of radius R. Obtain the expressions for the electric field (E) and electric potential (V) at a point 0 < x < R.
Show on a plot the variation of E and V with x for 0 < x < 2R.
Concept: Flow of Electric Charges in a Metallic Conductor
Two metallic wires, P1 and P2 of the same material and same length but different cross-sectional areas, A1 and A2 are joined together and connected to a source of emf. Find the ratio of the drift velocities of free electrons in the two wires when they are connected (i) in series, and (ii) in parallel.
Concept: Cells in Series
Describe the working principle of a solar cell. Mention three basic processes involved in the generation of emf.
Concept: Potential Difference and Emf of a Cell
Why are Si and GaAs preferred materials for solar cells?
Concept: Potential Difference and Emf of a Cell
Why is potentiometer preferred over a voltmeter for comparison of emf. of cells?
Concept: Potential Difference and Emf of a Cell
Draw a circuit diagram to determine internal resistance of a cell in the laboratory?
Concept: Measurement of Internal Resistance of a Cell
Plot a graph showing variation of voltage vs the current drawn from the cell. How can one get information from this plot about the emf of the cell and its internal resistance?
Concept: Cells, Emf, Internal Resistance
State Kirchhoff's rules and explain on what basis they are justified.
Concept: Kirchhoff’s Laws
Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of (11/3) Ω?
Concept: Kirchhoff’s Laws
Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of (11/5) Ω?
Concept: Kirchhoff’s Laws
Define the term 'electrical conductivity' of a metallic wire. Write its S.I. unit.
Concept: Specific Resistance
Show variation of resistivity of Si with temperature in a graph ?
Concept: Temperature Dependence of Resistance
A potentiometer wire of length 1.0 m has a resistance of 15 Ω. It is connected to a 5 V battery in series with a resistance of 5 Ω. Determine the emf of the primary cell which gives a balance point at 60 cm.
Concept: Cells, Emf, Internal Resistance
In the circuit shown in the figure, find the total resistance of the circuit and the current in the arm AD.
Concept: Ohm's Law
Three concentric metallic shells A, B and C or radii a, b and c (a < b < c) have surface charge densities + σ, −σ and + σ, respectively as shown in the figure
If shells A and C are at the same potential, then obtain the relation between the radii a, b and c.
Concept: Flow of Electric Charges in a Metallic Conductor
A cell of emf ‘E’ and internal resistance ‘r’ draws a current ‘I’. Write the relation between terminal voltage ‘V’ in terms of E, I and r ?
Concept: Cells, Emf, Internal Resistance
A heating element is marked 210 V, 630 W. What is the value of the current drawn by the element when connected to a 210 V dc source?
Concept: Resistivity of Various Materials
