# Density

## Trending Questions

**Q.**Mass is non-uniformly distributed on the circumference of a ring of radius α and center at origin. let b the disatnce of center of mass of the ring from origin

- b<α
- 0≤b≤α
- b>α
- b=α

**Q.**A body weighs 50 g in air and 40 g when completely immersed in water. How much it will weigh when immersed completely in a liquid of relative density 1.5?

- 30 g
- 35 g
- 45 g
- 25 g

**Q.**Density of a mixture is ρ, when fluids of densities ρ1and ρ2 are mixed in the same proportion. Then:

- ρ=ρ1+ρ22
- ρ=2ρ1ρ2ρ1+ρ2
- ρ=ρ21ρ2
- ρ=ρ22ρ1

**Q.**Three liquids of densities d, 2d and 3d are mixed in equal proportions of weights. What is the relative density of the mixture, if d is the density of water?

- 117
- 1811
- 139
- 2318

**Q.**The centre of mass of a solid hemisphere of radius 8 cm is x cm from the centre of the flat surface. Then value of x is ______.

**Q.**The density of alcohol is 780 kg/m3. Its relative density is

- 7.8 g/cm3
- 7.8
- 7.8 kg/m3
- 0.78

**Q.**The density of a solid metal sphere is determined by measuring its mass and its diameter, the maximum error in the density of the sphere is (x100)%. If the relative errors in measuring the mass and the diameter are 6.0 % and 1.5 % respectively, the value of x is

**Q.**1 kilogram of cotton and 1 kilogram of iron are weighed in a vacuum then which one of them will be more.

**Q.**Two substances of relative densities ρ1 and ρ2 are mixed in equal volumes and the relative density of the mixture is 4. When they are mixed in equal masses, the relative density of the mixture is 3. The values of ρ1 and ρ2 are

- ρ1=6 and ρ2=2
- ρ1=12 and ρ2=4
- None of these
- ρ1=3 and ρ2=5

**Q.**A uniform solid hemisphere of radius R is immersed into a liquid of density \(\rho\) as shown. The base of the hemisphere is at distance R from the surface of the liquid. Ignore atmospheric pressure. The force by the liquid on the curved surface of the hemisphere is

**Q.**

Density of ice is ρ and that of water is σ. What will be the decrease in volume when a mass M of ice melts

**Q.**A bat used in sports of cricket is cut at the location of its centre of mass shown in the figure. Then

- the masses of both the pieces will be same
- mass of part II would be larger
- mass of part I would be thrice the mass of part II
- mass of part I would be larger

**Q.**A piece of solid weighs 120 g in air and 80 g when completely immersed in water. The relative density of solid is

- 32
- 43
- 3
- 2

**Q.**

Suppose the tube in the previous problem is kept vertical with A upward but the other conditions remain the same. The separation between the cross sections at A and B is 1516 cm. Repeat parts (a), (b) and (c) of the previous problem. Take g = 10 ms−2.

**Q.**A simple pendulum of mass ′m′, length ′l′ and charge ′+q′ suspended in the electric field produced by two conducting parallel plates as shown in the figure. The value of deflection of pendulum in equilibrium position will be

(C1 and C2 are the capacitance of capacitors formed by parallel plates, without medium in between and with medium in between, respectively.)

- tan−1[qmg×C1(V2−V1)(C1+C2)(d−t)]
- tan−1[qmg×C2(V2−V1)(C1+C2)(d−t)]
- tan−1[qmg×C2(V1+V2)(C1+C2)(d−t)]
- tan−1[qmg×C1(V1+V2)(C1+C2)(d−t)]

**Q.**Two liquids A and B are at 30∘ C and 20∘ C, respectively. When they are mixed in equal masses, the temperature of the mixture is found to be 26∘ C. The ratio of their specific heat is

- 2:3
- 4:3
- 3:4
- 3:2

**Q.**Three liquids of densities d, 2d and 3d are mixed in equal volumes. Then the density of the mixture is

- d
- 3d
- 5d
- 2d

**Q.**5 g of steam at 100∘C is mixed with 10 g of ice at 0∘C. At equilibrium, the mixture contains pq gram of steam. Find (p+q).

(Given: swater=1 cal/g∘C, Lf=80 cal/g, Lv=540 cal/g)

**Q.**In an experiment of measuring specific heat of a liquid, a stream of liquid flows at a steady rate of 5g/s over an electrical heater dissipating 135W and a temperature rise of 5K is observed. On increasing the rate of flow to 10g/s, the same temperature rise is produced with a dissipation of 235W. Find the specific heat (J/gK) of the liquid. (Assume heat loss to the surrounding in both the cases is same.)

**Q.**A sample of an ideal gas has pressure p0, volume V0 and temperature T0. It is isothermally expanded to twice its original volume. It is then compressed at constant pressure to have the original volume V0. Finally, the gas is heated at constant volume to get the original temperature. The heat absorbed in the process is

- p0V0[In 2+2]
- p0V0[In 2−12]
- p0V0[In 2+32]
- p0V0[In 2+12]

**Q.**A piece of brass of volume 30 cm3 has a mass of 252 g. Fin the density of brass in gcm−3.

**Q.**A calorimeter of mass 0.2 kg and specific heat 900J/kg−K. Containing 0.5 kg of a liquid of specific heat 2400J/kg−K. Its temperature falls from 60∘C to 55∘C in one minute. The rate of cooling is

- 5 j/s
- 100 j/s
- 15 j/s
- 115 j/s

**Q.**

In making an alloy, a substance of specific gravity s1 and mass m1 is mixed with another substance of specific gravity s2 and mass m2; then the specific gravity of the alloy is

**Q.**The mass of a box measured by a grocer’s balance is 2.300 kg. Two gold pieces of masses 20.15 g and 20.17 g are added to the box. What is

i) The Total mass of the box.

ii) The difference in the masses of the pieces to correct significant figures.

**Q.**Equal masses of two liquids having densities d1 and d2 are mixed together. The density of the resulting mixture is

- d1+d22
- d1−d2d1d2
- d1d2d1+d2
- 2d1d2d1+d2

**Q.**The correct formula for specific gravity of a substance is

- SG=Density of substanceDensity of water at 0∘C
- SG=Density of waterDensity of substance
- SG=Density of subtanceDensity of water at 4∘C
- SG=Gravity forceMass

**Q.**A sphere of mass 5 kg and volume 2.2×10−4 m3 is completely immersed in water. Find the buoyant force exerted by water on the sphere.

Density of water =1000 kg-m−3 and take g=10 m/s2

- 2.1 N
- 2.2 N
- 2.4 N
- 2.3 N

**Q.**How much steam at 100∘ will just melt 64 gm of ice at −10∘C?

**Q.**A mass of 1 kg is suspended by a string A. Another string C is connected to its lower end (see figure). If the string C is stretched slowly, then

- None of the strings will break
- The portion BC of the string will break

- None of the above

- The portion AB of the string will break

**Q.**When 0.4 kg of water at 30∘ C is mixed with 0.15 kg of water at 25∘ C contained in a calorimeter, the final temperature is found to be 27∘ C, find the water equivalent of the calorimeter.

- 1 kg
- 0.5 kg
- 1.5 kg
- 0.450 kg