COMEDK Mock Test - 8 - JEE MCQ

Dot product of two different unit vectors is 0 and dot product of two same unit vectors is 1. Cross product of two different unit vectors taken according to right hand thumb rule is the other vector. Cross product of two same unit vectors is 0.

For t₁ - t₂, Charging graph
For t₂ - t₃, Discharging graph

By the principle of superposition of fields

Here  = net field at the centre of hole due to entire mass

 = field due to remaining mass

 = field due to mass in hole = 0

Since 15 minutes = 5 x 3 minutes = 5 half-lives, the number of nuclei left after 15 minutes = 1/2⁵ = 1/32 of the original number

Therefore, the mass of 16 g sample left after 15 minutes = 16/32 = 0.5 g

Hence, the correct choice is (d).

When photon strikes with the electron it completely transfers it’s energy to the electron as during photoelectric experiment the threshold frequency required is used by the electron to eject from the atom which is also called the work function and the remaining energy in electron is kinetic energy which can be measured. Now (before collision) since photon is a particle it must have mass and thus it has energy equivalent to E=mc2 .
After collision when it completely transfers it’s energy to electron thus E=0
And therefore 0=mc2 thus i guess photon vanishes.
 

Explanation:

The theory for ideal gases makes the following assumptions

1. Gases consist of particles in constant, random motion. They continue in a straight line until they collide with something—usually each other or the walls of their container.

2. Particles are point masses with no volume. The particles are so small compared to the space between them, that we do not consider their size in ideal gases.

3. No molecular forces are at work. This means that there is no attraction or repulsion between the particles.

4. Gas pressure is due to the molecules colliding with the walls of the container. All of these collisions are perfectly elastic, meaning that there is no change in energy of either the particles or the wall upon collision. No energy is lost or gained from collisions.

5. The time it takes to collide is negligible compared with the time between collisions.

6. The kinetic energy of a gas is a measure of its Kelvin temperature. Individual gas molecules have different speeds, but the temperature and kinetic energy of the gas refer to the average of these speeds.

7. The average kinetic energy of a gas particle is directly proportional to the temperature. An increase in temperature increases the speed in which the gas molecules move.

8. All gases at a given temperature have the same average kinetic energy.

9. Lighter gas molecules move faster than heavier molecules.

The density of ball should be greater than liquid 1 because it sinks in it.
Also density of ball should be less than density of liquid 2 as it floats on it.

i.e. 
= = 0.4 × 10^-4
⇒ 
= 0.4 × 10^-4

M = m × 14 cm = m × 14/100
= 
= 4 × 10^-4 × 7203.82 = 2.88 J/T

Total vapour pressure (VP) of mixture = VP of pentane in mixture + VP of hexane in mixture
P_T = (Mole fraction of pentane × VP of pentane) + (Mole fraction of hexane × VP of hexane)
P_T = 
VP of pentane in mixture = VP of mixture × Mole fraction of pentane in vapour
88 = 184 x Mole fraction of pentane in vapour
Or, mole fraction of pentane in the vapour phase = 88/184 = 0.4782 

 due to common ion effect.
x⋍10⁻⁴M

"if and only if" is TRUE when both conditions are the SAME truth value. Since "x + x = 3x" is false, the first condition must also be false. 2x - x = 2x is false.

Every whole number is either odd or even.
A whole number is even if it can be divided evenly by two; the numbers 2, 4, 6, 8, 10, 12, . . . are even.
In this question we are given the information that n is an odd number.
Because n is odd, it must be one of the numbers 1, 3, 5, 7, 9, 11, 13, 15, and so on.
Now we have to reason mathematically.
If n is a member of this “odd” list, then what can we say for sure about n +1?
If we add 1 to each number in the odd list, we get the “ n +1 ” list: 2, 4, 6, 8, 10, 12, 14, 16, and so on, which are even numbers.