A parallel plate capacitor having plates of area S and plate separation d, has capacitance C₁ in air. When two dielectrics of different relative permittivities ($$\varepsilon $$₁ = 2 and $$\varepsilon $$₂ = 4) are introduced between the two plates as shown in the figure, the capacitance becomes C₂. The ratio $${{{C_2}} \over {{C_1}}}$$ is

An ideal monoatomic gas is confined in a horizontal cylinder by a spring loaded piston (as shown in the figure). Initially the gas is at temperature T₁, pressure P₁ and volume V₁ and the spring is in its relaxed state. The gas is then heated very slowly to temperature T₂, pressure P₂ and volume V₂. During this process the piston moves out by a distance x.

Ignoring the friction between the piston and the cylinder, the correct statements is/are

A fission reaction is given by $$_{92}^{236}U \to _{54}^{140}Xe + _{38}^{94}Sr + x + y$$, where x and y are two particles. Considering $$_{92}^{236}U$$ to be at rest, the kinetic energies of the products are denoted by $${K_{Xe}},{K_{Sr}},{K_x}(2MeV)$$ $$ \text { and } \mathrm{K}_{\mathrm{y}}(2 \mathrm{MeV}) $$, respectively. Let the binding energies per nucleon of $$_{92}^{236}U$$, $$_{54}^{140}Xe$$ and $$_{38}^{94}Sr$$ be 7.5 MeV, 8.5 MeV and 8.5 MeV, respectively. Considering different conservation laws, the correct options is/are

Two spheres P and Q for equal radii have densities $$\rho$$₁ and $$\rho$$₂, respectively. The spheres are connected by a massless string and placed in liquids L₁ and L₂ of densities $$\sigma$$₁ and $$\sigma$$₂ and viscosities $${\eta _1}$$ and $${\eta _2}$$, respectively. They float in equilibrium with the sphere P in L₁ and sphere Q in L₂ and the string being taut (see figure) If sphere P along in L₂ has terminal velocity v_P and Q alone in L₁ ha terminal velocity v_Q, then