Question 3 :
In comparing e.m.f.s of 2 cells with the help of potentiometer, at the balance point, the current flowing through the wire is taken from:<br/>

Question 4 :
The resistance of a semiconductor material(germanium or silicon) ________with risein temperature.

Question 6 :
A student while performing an experiment was surprised to find that when two identical cells are either connected in series or in parallel across a $2\Omega$ resistor, the same current passes through the resistor. What is the internal resistance of each cell?

Question 7 :
There are three red colored bands on a carbon resistor. What is its resistance ?

Question 9 :
Consider a circuit which contains a resistancefree battery and a single resistance $R$ . If a secondresistance is added in parallel with $R$ .

Question 12 :
Consider the following statements A and B and&#160;identify the correct answer<br/>A : Thermistors can have only -ve temperature&#160;coefficient of resistors.<br/>B : Thermistors with -ve temperature coefficients&#160;of resistance are used as resistance&#160;thermometers to measure low temperature of the&#160;order of 10K<br/>

Question 13 :
If the length of potentiometer wire is increased, then the length of the previously obtained balance point will

Question 14 :
If the balancing length for a cell of emf E is 60 cm, the value of E will be

Question 16 :
Match list - I with List - II<br/>List - I &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; List - II<br/>a) Thermistor &#160; &#160; &#160;e) High positive $\alpha $<br/>b) Carbon &#160; &#160; &#160; &#160; &#160; &#160;f)&#160;$\alpha $&#160;almost zero<br/>c) Nichrome &#160; &#160; &#160; &#160;g) either positive or&#160;negative&#160;$\alpha $<br/>d) Constantan &#160; &#160;&#160;h) Negative&#160;$\alpha $<br/>manganin<br/>

Question 17 :
Two cells of emf's 1.25V and 0.75V having equal internal resistance are connected in parallel. The effective emf is<br>

Question 18 :
The effective resistance of a circuit containing resistances in parallel is.

Question 19 :
The length of a conductor is doubled and its radius is halved, its specific resistance is

Question 21 :
If the length of a material changes 4 times and area changes 2 times. Then the resistivity of the material will be changing

Question 22 :
Two resistors of resistance $\displaystyle { R }_{ 1 }$ and$\displaystyle { R }_{ 2 }$ having$\displaystyle { R }_{ 1 }&gt;{ R }_{ 2 }$ are connected in parallel. For equivalent resistance R, the correct statement is

Question 23 :
Identify the changes in a circuit on adding a light bulb in parallel to the actual resistance of the circuit. It will:<br/>

Question 25 :
Kirchoffs law of junctions is also called the law&#160;of conservation of:<br/>

Question 26 :
Three equal resistors connected in series across a source of e.m.f dissipate 10 watts of power. What will be the power dissipated in watts if the same resistors are connected in parallel across the same source of e.m.f?

Question 27 :
Two unequal resistances are connected in parallel. Which of the following statement is true<br>

Question 28 :
Which physical quantity cannot be determined with the help of potentiometer?<br>

Question 30 :
Two sources of equal emf are connected to an external resistance R. The internal resistance of the two sources are $R_1$ and $R_2$ $(R_2 &gt; R_1)$. If the potential difference across the source having internal resistance $R_2$ is zero, then.

Question 32 :
A battery of 20 cells (each having e.m.f. 1.8 volt and internal resistance 0.1 ohm) is charged by 220 volts and the charging current is 15A. The resistance to be put in the circuit is<br>

Question 33 :
The mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an n-type semiconductor, the density of electrons is $10^{19}m^{-3}$ and their mobility is $1.6 m^2/(V.s)$ then the resistivity of the semiconductor (since it is an n-type semiconductor&#160;contribution of holes is ignored) is close to:

Question 34 :
A potentiometer consists of a wire of length 4m and resistance 10$\Omega$. It is connected to a cell of e.m.f. 3V. The potential gradient of wire is

Question 35 :
The e.m.f. of a cell is _____ the voltage across its terminals when no current flows. Fill in the blank.

Question 37 :
For a cell terminal P.D. is 2.2 V when circuit isopen and reduces to 1.8 V when cell is connectedto a resistance of R = 5. Determine internalresistance of cell (r) is then : -

Question 38 :
Find the effective resistance, when $1\Omega$,$10\Omega$ and$4\Omega$ resistances are connected in series.

Question 39 :
The daniel cell is balanced on $125 cm$ length of a potentiometer. Now, the cell is short circuited by a resistance of $2\Omega $ and the balance is obtained at $100 cm$. The internal resistance of the daniel cell is :

Question 40 :
A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves: