The power of a combination of convex lens of focal length 40 cm and a concave lens of focal length 25 cm when placed in contact is :

A network of four \( 9 \mu F \) capacitors is connected to a 500 V supply, as shown. In the context of this, identify the correct statements.

(A) \( C_4 \) is connected in parallel to the combination of \( C_1, C_2 \) and \( C_3 \).
(B) The equivalent capacitance of the combination \( C_1, C_2, C_3 \) and \( C_4 \) is \( 12 \mu F \).
(C) The charge on \( C_4 \) is \( 4.5 \times 10^{-3} \text{ C} \).
(D) The charge stored on \( C_1 \) and \( C_4 \) is the same.
Choose the correct answer from the options given below:

Which of the following statements are true?
(A) Rheostat can be used both as a variable resistance and a potential divider.
(B) An electrical circuit is functional only if all the components of the circuit are connected in proper order, assuming that all circuit components/ devices are in working condition and key is closed.
(C) An open circuit means a break in some part of a circuit which could be deliberate such as a key in open position or a fault such as broken wire or burnt out component(s) or loose connection.
(D) Rheostat as a potential divider gives variable resistance.
Choose the correct answer from the options given below:

To get eight images of a single object one should have two plane mirror at an angle of :

A non-polar dielectric material is placed in an external electric field. Choose the correct statement(s) from the following:
(A) There will be no change in the positions of positive and negative charges inside the dielectric.
(B) The positive charges of molecules will shift opposite to the direction of the electric field.
(C) The negative charges of molecules will shift in the direction of the electric field.
(D) The positive charges of the molecules will shift in the direction of the field and negative charges of the molecules will shift opposite to the field.
Choose the correct answer from the options given below:

A very long solenoid has 800 turns per unit length. A current of 1.6 A flows through it. Then the magnetic induction in the middle of the solenoid on its axis is approximately :
(1) \( 16 \times 10^{-4} \text{ T} \)
(2) \( 8 \times 10^{-4} \text{ T} \)
(3) \( 32 \times 10^{-4} \text{ T} \)
(4) \( 4 \times 10^{-4} \text{ T} \)

A circular coil with 5 turns, each of radius 7 cm, carries a current of 1.4 A. The magnetic field at the center of the coil is:

The plane \(x(1+2 \lambda)+y(2+\lambda)+z(3-\lambda)=0\) passes through the intersection of :

For a general electrochemical reaction of the type :
\(a A+b B \rightarrow c C+d D\)
involving transfer of \(n\) electrons, the Nernst equation can be writtenas :

If the mean of a binomial distribution is 12 and its standard deviation is 2 , then the number of trials is :

A message signal of peak voltage 20 V is used to modulate a carrier wave of amplitude 40 V in amplitude modulation. The ratio of maximum amplitude and minimum amplitude in amplitude modulated signal is:

A card is selected at random from a pack of 52 playing cards.The selected card is a queen.The probability that this card is a card of spade is :

Observe the given diagram and answer the following question :

Genetically engineered insulin was made by Eli Lilly in 1983 by using :