JEE 2020: Weekly Quiz 7 (06.07.2019) for JEE & BITSAT Exams

Question 1

When electric bulbs of same power, but different marked voltage are connected in series across the power line, their brightness will be

Question 2

Three identical bulbs each of resistance 2Ω are connected as shown. The maximum power that can be consumed by individual bulb is 32W, then the maximum power (in Watt) consumed by the combination is :

Question 3

A battery of internal resistance 4 Ω is connected to the network of resistance as shown in the Figure. In order to get maximum power to the network, the value of R in ohm should be

Question 4

Six identical conducting rods are joined as shown in figure. Points A and D are maintained at temperature of 200°C and 20°C respectively. The temperature of junction B will be :

Question 5

A metallic rod of cross-sectional area 9.0 cm² and length 0.54 m, with the surface insulated to prevent heat loss, has one end immersed in boiling water and the other in ice-water mixture. The heat conducted through the rod melts the ice at the rate of 1 gm for every 33 sec. The thermal conductivity of the rod is (Take L_f of ice = 3.34 x 10⁵ J/kg)

Question 6

A hollow sphere of inner radius R and outer radius 2R is made of a material of thermal conductivity K. It is surrounded by another hollow sphere of inner radius 2R and outer radius 3R made of same material of thermal conductivity K. The inside of smaller sphere is maintained at 0°C and the outside of bigger sphere at 100°C . The system is in steady state. The temperature of the interface will be :

Question 7

Three conducting rods of same material and cross-section are shown in figure. Temperatures of A, D and C are maintained at 20°C, 90°C and 0°C . The ratio of lengths of BD and BC if there is no heat flow in AB is :

Question 8

A solid ball is completely immersed in a liquid. The coefficients of volume expansion of the ball and liquid are 3 × 10^-6 per °C and 8 x 10^-6 /^oC respectively. The percentage change in up thrust when the temperature is increased by 100 °C is

Question 9

A thin copper wire of length L increase in length by 1% when heated from temperature T₁ to T₂. What is the percentage change in area when a thin copper plate having dimensions 2L × L is heated from T₁ to T₂?

Question 10

If two rods of length L and 2L having coefficients of linear expansion α and 2α respectively are connected so that total length becomes 3L, the average coefficient of linear expansion of the composition rod equals:

Question 11

Which among the following is incorrect for physisorption?

Question 12

When 0.5mole glucose is dissolved in 1.5moles of water the vapour pressure is

Question 13

van’t Hoff factor is defined as –

Question 14

In a hypertonic solution, the cell becomes _______.

Question 15

Glucose is added to 1L of water to such an extent that the ratio of ΔT_f / K_f becomes 10^-3. The mass of glucose added is-

Question 16

CH₃COOH dimerises in benzene solution, the value of van’t Hoff factor of dimerisation of acetic acid is 0.6 then calculate the % of dimerisation of acetic acid?

Question 17

Consider a vessel containing a gas X₂. The gas is heated from 0 ^oC to 100 ^oC at 1.0 atm pressure. The initial volume of the gas is 20 L. The final volume is

Question 18

When mercuric iodide is added to aqueous solution of KI the

Question 19

An ideal solution was obtained by mixing methanol and ethanol. If the partial vapour pressure of methanol and ethanol are 2.619 kPa and 4.556 kPa respectively, the composition of vapour (in terms of mole fraction) will be

Question 20

A sample of milk is found to contain 4% of butter fat by volume. The density of butter fat is 875 kg/m³ and that of milk is 1035 kg/m³. The density of skimmed milk is: