If the magnetic flux through a coil of 1200 turns increases from zero to \(5.4 \times 10^{-5} \text{ Wb}\) in \(2.7 \text{ ms}\), what is the magnitude of the induced emf during this time?

Two cells of emf \( E \) and \( 2E \) with internal resistances \( r \) and \( 3r \), respectively are connected in parallel. The emf and internal resistance of the combination is:

When a ray of light is incident at an angle of incidence \( 60^\circ \) on one face of an equilateral prism the angle of deviation is found to be minimum. The refractive index of the prism is :

Two capacitors of capacitances of \( 6 \, \mu F \) and \( 12 \, \mu F \) are connected in series with a 12 V battery. The total energy stored in the combination is

Total internal reflection can take place only, if

Which of the following statements are correct?
A. In a photon-particle collision number of photons are conserved.
B. The photoelectric current is directly proportional to the intensity of incident light.
C. The photoelectric emission is an instantaneous process.
D. Maximum kinetic energy of photoelectrons depend on the intensity of incident radiation.
E. The threshold frequency is different for different metals.
Choose the correct answer from the options given below:

Electrical energy is transmitted over long distances at high alternating voltages by the use of a transformer. Choose the correct statements from the following :
(A) Higher voltage implies less power loss.
(B) The alternating magnetic flux induces eddy currents in the iron core and causes heating.
(C) Step up transformer increases the current by reducing the voltage in the above transformer.
(D) Transmission lines can be made thinner to reduce power loss.
Choose the correct answer from the options given below :

Three capacitors of capacitances 2 \(\mu F\), 3 \(\mu F\) and 6 \(\mu F\) are connected in series. The combination is connected to a 12 V supply. The respective potential differences across them will be

If \(A =\left(\begin{array}{cc}-a & b \\ c & a\end{array}\right)\) and \(A ^2= I\), where \(I\) is an Identity matrix of order 2, then which of the following is correct?

In an electromagnetic wave, the ratio of energy densities of electric and magnetic fields is :

Let \(A=\{1,2,3\}\) and \(R=\{(1,1),(1,3),(3,1),(2,2),(2,1),(3,3)\}\) be a relation on \(A\). Then, \(R\) is:

Read the passage carefully. Attempt the questions.
An overwhelming majority (99 per cent) of animals and nearly all plants cannot maintain a constant internal environment. Their body temperature changes with the ambient temperature. In aquatic animals, the osmotic concentration of the body fluids change with that of the ambient air and water osmotic concentration. These animals and plants are simply conformers. Considering the benefits of a constant internal environment to the organism, we must ask why these conformers had not evolved to become regulators. Recall the human analogy we used above; much as they like, how many people can really afford an air conditioner? Many simply 'sweat it out' and resign themselves to suboptimal performance in hot summer months. Very small animals are rarely found in polar regions. During the course of evolution, the costs and benefits of maintainin a constant internal environment are taken into consideration. Some species have evolved the ability to regulate, but only over a limited range of environmental conditions, beyond which they simply conform.
If the stressful external conditions are localised or remain only for a short duration, the organism has five other alternatives for survival.
Identify the statements which support the reason why small animals are rarely found in polar regions.
A. Small animals have larger surface area relative to their volume
B. Small animals have larger volume relative to their surface area
C. Shrews and humming birds are not found in polar region
D. Small animals have smaller surface area relative to their volume