Tag: properties of matter

Quizzes (22) Questions (194)

Questions Related to properties of matter

Multiple choice intermolecular forces: cohesive and adhesive forces surface tension properties of matter physics

On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because

  1. mercury is a metal

  2. density of mercury is greater than that of water

  3. cohesion of mercury is greater than its adhesion with glass

  4. cohesion of water is greater than its adhesion with glass
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mercury remains spherical on a glass plate due to greater cohesive force between mercury molecules than adhesive force between mercury and glass plate.

Multiple choice intermolecular forces: cohesive and adhesive forces surface tension properties of matter physics

A capillary tube of radius $0.25\ mm$ is submerged vertically in water so that $25\ mm$ of its length outside water. The radius of curvature of the meniscus will be $(T = 7.5\times 10^{-3} N/m)$.

  1. $0.2\ mm$

  2. $0.4\ mm$

  3. $0.6\ mm$

  4. $0.8\ mm$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$h= \dfrac{2T}{dgx}$

$h= \dfrac{2\times 7.5 \times {10}^-3} {1000 \times 10 \times d}$
$h=25mm$
$d= 0.6 mm$

Multiple choice forces on solids elastic and plastic substances forces and matter properties of matter physics

On suspending a weight $Mg$ the length $l$ of elastic wire and area of cross section $A$ its length becomes double the initial length. The instantaneous stress action on the wire is:

  1. $\dfrac{Mg}{A}$

  2. $\dfrac{Mg}{2A}$

  3. $\dfrac{2Mg}{A}$

  4. $\dfrac{4Mg}{A}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Stress is defined as the internal restoring force per unit area. When the wire is stretched to double its length, the instantaneous cross-sectional area decreases due to the Poisson effect, but in standard textbook problems of this type, it is assumed the force is applied to the original area or the question implies the stress at the point of doubling. However, based on standard stress-strain definitions for this specific problem type, 2Mg/A is the accepted answer.

Multiple choice forces on solids elastic and plastic substances forces and matter properties of matter physics

The velocity of the transverse waves in a wire of density $8000kg/m^3$ is $300 m/s$. The tensile stress in the wire is then

  1. $7.2\times10^8 N/m^2$

  2. $6.8\times10^8 N/m^2$

  3. $5.2\times10^8 N/m^2$

  4. $8.4\times10^8 N/m^2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Given density = 8000 $kg/{ m }^{ 3 }$ and velocity =300 m/s

Also we know velocity of transverse wave  $\text{V}=\sqrt { \dfrac { T }{ \mu  }  } \text{where T= tension and}\quad \mu =\text{mass per unit lenght}\quad =\dfrac { m }{ L } \quad $
also $\text{Density}\quad \rho =\dfrac { mass }{ Area\times Lenght } \ \rho \times A=\dfrac { m }{ L } $
$\text{Tension T}=\rho A{ V }^{ 2 }$
We know stress $\sigma =\dfrac { Force }{ Area } =\dfrac { Tension }{ Area } =\dfrac { { V }^{ 2 }\rho A }{ A } ={ V }^{ 2 }\rho $
${ 300 }^{ 2 }\times 8000=7.2\times { 10 }^{ 8 }\dfrac { N }{ { m }^{ 2 } } $ 

Multiple choice forces on solids elastic and plastic substances forces and matter properties of matter physics

An external force of $10\ N$ acts normally on a square area of each side $50\ cm$. The stress produced in equilibrium state is

  1. $10\ N/m^{2}$

  2. $20\ N/m^{2}$

  3. $40\ N/m^{2}$

  4. $50\ N/m^{2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Stress = Force / Area. The force is 10 N. The side of the square is 50 cm = 0.5 m, so the area is 0.5 * 0.5 = 0.25 m^2. Stress = 10 / 0.25 = 40 N/m^2.

Multiple choice forces on solids elastic and plastic substances forces and matter properties of matter physics

The length of wire is increased by $0.06\%$ by a load of $40N$ whose tensile modulus is $20\times10^{10}N/M^2$.The subjected stress is 

  1. $12\times10^{10}N/m^2$

  2. $1.2\times10^{8}N/m^2$

  3. $120N/m^2$

  4. $1.25\times10^6N/m^2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\cfrac{\triangle l}{l}\times 100=0.06$

$\implies \cfrac{\triangle l}{l}=\cfrac{0.06}{100}$
Now stress $=\cfrac{20\times 10^{10}\times 0.06}{1000}\=1.2\times 10^8\ N /m^2$

Multiple choice forces on solids elastic and plastic substances forces and matter properties of matter physics

According to $C.E$ van der Waal, the interatomic potential varies with the average interatomic distance $(R)$ as 

  1. $R^{-1}$

  2. $R^{-2}$

  3. $R^{-4}$

  4. $R^{-6}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

According to the relation

$ V(r)=\dfrac{-3}{4}\dfrac{{{\alpha }^{2}} _{0}l}{{{(4\pi {{\varepsilon } _{0}})}^{2}}{{R}^{6}}} $

$ V(r)\propto \dfrac{1}{{{R}^{6}}} $

$ V(r)\propto {{R}^{-6}} $