What is the position and nature of image formed by lens combination shown in figure ? (f1, f2 are focal lengths)

Formation of real image using a biconvex lens is shown below : If the whole set up is immersed in water without disturbing the object and the screen positions, what will one observe on the screen ?

A galvanometer, whose resistance is 50 ohm, has 25 divisions in it. When a current of 4 $$\times$$ 10–4 A passes through it, its needle ( pointer) deflects by one division. To use this galvanometer as a voltmeter of range 2.5 V, it should be connected to a resistance of :

A 200 $$\Omega$$ resistor has a certain color code. If one replaces the red color by green in the code, the new resistance will be :

For the circuit shown, with R1 = 1.0W, R2 = 2.0 W, E1 = 2 V and E2 = E3 = 4 V, the potential difference between the points 'a' and 'b' is approximately (in V):

In the circuit shown, a four-wire potentiometer is made of a 400 cm long wire, which extends between A and B. The resistance per unit length of the potentiometer wire is r = 0.01 $$\Omega$$/cm. If an ideal voltmeter is connected as shown with jockey J at 50 cm from end A, the expected reading of the voltmeter will be :-

A cell of internal resistance r drives current through an external resistance R. The power delivered by the cell to the external resistance will be maximum when :-

In the figure shown, what is the current (in Ampere) drawn from the battery ? You are given: R1 = 15$$\Omega$$, R2 = 10 $$\Omega$$, R3 = 20 $$\Omega$$, R4 = 5$$\Omega$$, R5 = 25$$\Omega$$, R6 = 30 $$\Omega$$, E = 15 V

A wire of resistance R is bent to form a square ABCD as shown in the figure. The effective resistance between E and C is : (E is mid-point of arm CD)

A moving coil galvanometer has resistance 50$$\Omega$$ and it indicates full deflection at 4mA current. A voltmeter is made using this galvanometer and a 5 k$$\Omega$$ resistance. The maximum voltage, that can be measured using this voltmeter, will be close to :

A metal wire of resistance 3 $$\Omega$$ is elongated to make a uniform wire of double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle make an angle 60° at the centre, the equivalent resistance between these two points will be :-

The resistance of a galvanometer is 50 ohm and the maximum current which can be passed through it is 0.002 A. What resistance must be connected to it in order to convert it into an ammeter of range 0 – 0.5 A ?

In a conductor, if the number of conduction electrons per unit volume is 8.5 × 1028 m–3 and mean free time is 25ƒs (femto second), it's approximate resistivity is :- (me = 9.1 × 10–31 kg)

A current of 5 A passes through a copper conductor (resistivity = 1.7 × 10–8 $$\Omega$$m) of radius of cross-section 5 mm. Find the mobility of the charges if their drift velocity is 1.1 × 10–3 m/s.

In a meter bridge experiment, the circuit diagram and the corresponding observation table are shown in figure .tg {border-collapse:collapse;border-spacing:0;width:100%} .tg td{font-family:Arial, sans-serif;font-size:14px;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:black;} .tg th{font-family:Arial, sans-serif;font-size:14px;font-weight:normal;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:black;} .tg .tg-s6z2{text-align:center} .tg .tg-baqh{text-align:center;vertical-align:top} .tg .tg-hgcj{font-weight:bold;text-align:center} .tg .tg-amwm{font-weight:bold;text-align:center;vertical-align:top} SI. No. R($$\Omega$$) l(cm) 1. 1000 60 2. 100 13 3. 10 1.5 4. 1 1.0 Which of the readings is inconsistent?

In an experiment, the resistance of a material is plotted as a function of temperature (in some range). As shown in the figure, it is a straight line. One may conclude that :

A moving coil galvanometer allows a full scale current of 10–4 A. A series resistance of 2 M$$\Omega$$ is required to convert the above galvanometer into a voltmeter of range 0-5 V. Therefore the value of shunt resistance required to convert the above galvanometer into an ammeter of range 0.10 mA is :

In the given circuit, an ideal voltmeter connected across the 10$$\Omega$$ resistance reads 2V. The internal resistance r, of each cell is:

Space between two concentric conducting spheres of radii a and b (b > a) is filled with a medium of resistivity $$\rho$$. The resistance between the two spheres will be :

The resistive network shown below is connected to a D.C. source of 16 V. The power consumed by the network is 4 Watt. The value of R is: