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Which kind of charge moves: positive charges (protons) or negative charges (electrons)?
Is electric current a scalar or vector quantity? Sate the smaller unit of current.
What is electric potential?
Calculate the work done in moving a charge of 5 coulombs from a point at 20 to another at 30 V.
Electrons are responsible for conduction in a conductor. The speed of electron is not very high. Then, how the bulb is on immediately even through the switch and bulb are far away from each other in a household circuit?
A wire of resistance 20 Ω is bent to form a closed square. What is the resistance across a diagonal of the square?
How does the resistance of an ohmic conductor depend on the applied voltage?
An electric fan/motor becomes warm when continuously used for a long time. Why?
State difference between the wire used in the element of an electric heater and in a fuse wire.
A 9 Ω resistance is cut into three equal parts and connected in parallel. Find the equivalent resistance of the combination.
An electrical appliance draws a current of 0.5 A when applied potential difference across it is 220V. Calculate the amount of charge flowing through it in 30 minutes.
The resistivity of copper is 1.7 × 10-8 Ωm. What length of copper wire of diameter 0.1 mm will have a resistance of 34Ω?
Draw a schematic diagram of an electric circuit consisting of battery of five 2V cells, a 20 Ω resistor, a 30 Ω resistor, a plug key, all connected in series. Calculate the value of current flowing through the 20 Ω resistor and the power consumed by the 30 Ω resistor.
What do the following circuit symbols represent?
The potential difference between the terminals of an electric heater is 60V when it draws a current of 4A from the source. Find the resistance of heater when in use.
A wire of 3Ω resistance and 15cm in length is stretched to 45 cm length. Calculate (i) New resistance.
Assuming the wire has uniform cross section area.
A wire of resistance 10Ω is bent in the form of a closed circle. What is the effective resistance between the two points at the ends of any diameter of the circle?
An electric lamp is marked 26 W, 220V. It is used for 10 hours daily. Calculate
its resistance while glowing.
energy consumed in kWh per day.
The electric power consumed by a device may be calculated by the using either of the two expressions P = I2R or P = V2/R. The first expression indicates that it is directly proportional to R whereas the second expression indicates inverse proportionality. How can the seemingly different dependence of P on R in these expressions be explained.
A simple circuit consists of a resistor, a battery, and connecting wires.
How must a voltmeter be connected to a resistor in order to read the potential difference across it?
How must an ammeter be connected in a circuit to correctly read the current?
Draw the circuit diagram.
A wire of given material having length l and area of cross-section A, has a resistance of 2 Ω. Find the resistance of another wire of same material having length 2l and are of cross-section A/2.
Calculate the ratio of the equivalent resistance of the above two wires in parallel combination to that in series combination.
Five resistors are connected in a circuit as shown. Find the ammeter reading when circuit is closed.
Three V-I graphs are drawn individually for two resistors and their series combination. out of A, B, C which one represents the graph for series combination of the other two? Give reason for your answer.
Identify the type of combination in which R1 and R2 are connected in the given circuit diagram.
Find the effective resistance of the combination.
Bulb is rated at 200 V, 100 W. Calculate its resistance. Five such bulbs are lighted for 4 hours daily. Calculate the units of electrical energy consumed per day. What would be the cost of using these bulbs per day at the rate of Rs. 4.00 per unit?
When a high resistance voltmeter is connected directly across a resister its reading is 2 V. An electric cell is sending the current of 0.4A, (measured by an ammeter) in the electric circuit in which a rheostat is also connected to vary the current.
Draw an equivalent labelled circuit for the given data.
Find the resistance of the resister.
Name and state the law applicable in the given case. A graph is drawn between a set of values of potential difference (V) across the resister and current (I) flowing through it. Show nature of graph thus obtained.
In a household electric circuit, different appliances are connected in parallel to one another. Give two reasons
An electrician puts a fuse of rating 5A in that part of domestic electrical circuit in which an electrical heater of rating 1.5 kW, 220V is operating. What is likely to happen in this case and why? What change, if any, needs to be made?
In the given circuit, connect a nichrome wire of length ‘L’ between points X and Y and note the ammeter reading.
(i) When this experiment is repeated by inserting another nichrome wire of the same thickness but twice the length (2L), what changes are observed in the ammeter reading?
(ii) State the changes that are observed in the ammeter reading if we double the area of cross-section without changing the length in the above experiment. Justify your answer in both the cases.
“Potential difference between points A and B in an electric field is 1 V”. Explain the above statement.
Find the value of current I in the circuit given below:
You have four resistors of 8 Ω each. Show how would you connect these resistors to have effective resistance of 8 Ω.
Shushant was doing an experiment by using an ammeter. Unfortunately, it fell from his hand and broke. Fearing the scolding of teacher, his group mates advised him not to tell the teacher, but he told her. On listening to him patiently, the teacher did not scold him as it was just and accident and used the opportunity to show the whole class the internal structure of ammeter.
What are the values displayed by Shushant?
What is the use of ammeter? How is it connected in the circuit?
State the aim of any one experiment where Shushant could have used the ammeter.
