Class 11th

The sum of “number off filled orbitals” and “number of vacant orbitals” upto valence shell of Fe is

The new white belt of a long horizontal conveyor is moving with a constant speed v = 3.0m/s. A small block of carbon is placed on the belt with zero initial velocity relative to the ground. The block will slip a bit before moving with the belt, leaving a black mark on the belt (figure). How long is that mark (in m) if the coefficient of kinetic friction between the carbon block and the belt is 0.20 and the coefficient of static friction is 0.30?

A calorimeter consists of 400g of water at $24°C.$ A 500g piece of copper at $100°C$ is thrown into the water and the equilibrium temperature is found to be $36.5°C.$  What is the molar heat capacity of copper in cal/mol k, given that 1 mol of copper has a mass of 63.5g? Neglect the heat capacity of the container.

A small elastic ball of mass m is placed at the apex of a $45°$  inclined plane as shown in the figure below. The ball is allowed to slip without friction down the plane (along the dotted line), hit the ground (as shown) and bounce along it. If the height of the inclined plane is h and the coefficient of restitution between the ball and the ground is 0.5, then the distance AB, as marked on the figure, will be N * h, where N is

A wave given by equation y = 1mm sin $\left(\frac{nx}{30}-5nt\right)$  is produced in a string 100m long of mass 1 kg. What is the tension (in N) in string? x is in m & t in sec.

A plastic ball is rising in water with terminal speed v. If we use a different plastic whose density is double that of the original ball but still less that density of water, keeping the radius same, the terminal speed would be:

The electric field line pattern for charges + 2q & - q are shown. Select the most appropriate diagram:-

Two blocks of same mass but different density ${\rho }_1\&{\rho }_2$ are floating in water. Block-2 has higher fraction of its volume submerged in water. If buoyant force on them are B₁ & B₂ :-

Assume temperature of 27^oC p = 10⁵ Pa, n = 1 mole diameter of air molecules as 10^-10m, which of the following is correct?