A resistor develops 800 J of thermal energy in 20 s on applying a potential difference of 20 V. Its resistance is

After how many half lives a radioactive substance will decay to 6.25% of its original value :

Two plane monochromatic waves propagating in the same direction with amplitudes \( 3A \) and \( 5A \) and differing in phase by \( \frac{2\pi}{3} \), superimpose. The amplitude of the resulting wave is :

The transverse nature of light is shown by

Which are the correct statements from given below:
A. Kirchhoff's junction rule is based on conservation of charge
B. Current is a vector quantity.
C. Current density is a vector quantity.
D. Resistance doesn't depend on dimension of conductor.
E. Resistivity depends on temperature.

A series combination of two capacitors \( C_1 = 3 \, \mu\text{F} \) and \( C_2 = 6 \, \mu\text{F} \) is connected in parallel with a third capacitor \( C_3 = 4 \, \mu\text{F} \). This system is connected to a 10 V battery. The total energy stored in the system is:

An astronomical telescope has a large aperture to

Question based on following passage: Adsorption is the process of attracting and retaining the adsorbate molecules on the surface of adsorbent. It is of two types i.e. Physisrption and chemisorption. To increase the rate of reaction, the substance called 'catalyst' is added. Promotors enhance the activity of catalyst while poison decrease the catalyst activity. Solutions may be true solution, suspension and colloids. Colloids are heterogenous but quite stable. On the basis of nature of interaction, colloids may be Lyophilic or Lyophobic. On the basis of type of dispersed phase particles, there may be multimolecular colloids, macromlecular colloids and associated colloids. The congulation of colloids may be done by boiling, dialysis or by mixing oppositely charged sols.
The Characteristic of physical adsorption is that it is :

Predict which of the following mixtures will show a positive deviation from Raoult's Law ?

Which of the following is not a property of \(\alpha\)-sulphur ?

The area (in sq. units) of the region \(\left\{(x, y): 3 x^2 \leq y \leq|x|\right\}\) is equal to :

Which one of the following diseases can be treated by human protein (a -1- antitrypsin) produced by transgenic animals?

Which of the following is an example of nuclear fusion ?