Measuring Mass

Q. If the size of a nucleus is 10thpower of -15meters is scales up to the tip of a sharp pin is 10thpower of -5meters , then what roughly is the size of the atom?

Q. The number of particle crossing per unit area perpendicular to Z axis per unit time is given by N=-D(N2-N1)/(Z2-Z1), where N2 and N1 are the number of particle per unit volume at Z2 and Z1 respectively. What is the dimensional formula for D?

Q. A particle of mass m and charge q moves with a constant velocity v along the positive x direction. It enters a region containing a uniform magnetic field B directed along the negative z direction, extending from x = a to x = b. The minimum value of v required so that the particle can just enter the region x > b is

1. $qbB/m$
2. $q(b-a)B/m$
3. $qaB/m$
4. $q(b+a)B/2m$

Q. A semi circular wire of radius R is rotated with angular velocity $\omega$ about an axis passing through one end and perpendicular to the plane of wire in a uniform magnetic field of magnitude $B_o$. $q$ is midpoint of the semicircle, then the ratio of potential difference between p and r to q and r is ($i.e{V}_{pr}:V_{qr})$

1. $\sqrt{2}:1$
2. 1:2
3. $\sqrt{3}:\sqrt{2}$
4. 2 :1

Q.

A hollow spherical body of inner and outer radii 6 cm and 8 cm respectively floats half-submerged in water. Find the density of the material of the sphere.

Q. 15.Radius of He nucleus is 3 fermi. The radius of 16 S 32 nucleus will be

Q. A long straight wire carries a certain current and produces a magnetic field $2\times {10}^{-4}Wb{m}^{-2}$at a perpendicular distance of $5$ $cm$ from the wire. A particle say 'c' having charge equal to that of an electron is situated at $5$ $cm$ from the wire moves with a velocity of ${10}^{7}m/s$ towards the wire perpendicularly. The magnitude of force experienced by the particle will be (charge of an electron =$-1.6\times {10}^{-19}C$ )

1. $3.2N$
2. $3.2\times {10}^{-16}N$
3. $1.6\times {10}^{-16}N$
4. $0$ $N$

Q.

If mass of earth is M, radius is R and gravitational constant is G, then work done to take 1 kg mass from earth surface to infinity will be

1. 

2. 

3. 

4. 

Q. A particle having specific charge s starts from rest in a region where the electric field has constant direction but magnitude verifying with time t as $E=E_{0}t$. In time t, it is observed that the particle acquires a velocity v after covering a distance x, then

1. $x=\frac{1}{2}\left(E_{0}s\right)t^3$
2. $x=\frac{1}{6}\left(E_{0}s\right)t^3$
3. $v=\left(E_{0}s\right)t^2$
4. $v=\frac{1}{25}\left(E_{0}s\right)t^2$

Q.

If $36.4\times {10}^{-15}$ g of mass is transferred when fur is rubbed with silk, find the number of electrons lost by fur? (mass of electron $=9.1\times {10}^{-31}$ kg).

Q.

Device used to measure mass of chemicals is ___________.

Q. A proton is accelerating in a cyclotron. It comes out of the cyclotron with the kinetic energy $K$. If it is required to have kinetic energy $4K$, then the radius of the circular path will be _____ times of its initial value.

1. $1$
2. $2$
3. $3$
4. $4$

Q.

What force will produce a moment of force$4.5N-m$, if the perpendicular distance between the force and the turning point is$20cm$?

Q. How does a thread (placed over on ice cube with a weight of 2 -2 kg on both sides ) passes through the ice cube and does not leaves any cuts on it?

Q.

Complete the following sentences:

The mass of a proton is ________ times that of an electron.

Q.

Brief description of dimensional analysis.

Q. The diagram shows a cuboid block made from a metal of density $2.5g/{cm}^3$
What is the mass of the block?

1. $8.0kg$
2. $16kg$
3. $50g$
4. $100g$

Q. Two spherical bodies of mass $M$ and $5M$ and radii $R$ and $2R$ released in free space with initial separation between their centres equal to $12R$. If they attract each other due to gravitational force only, then the distance covered by the smaller body before collision is

1. $4.5R$
2. $7.5R$
3. $1.5R$
4. $2.5R$

Q. The mass of an oxygen atom is 16.00 u. Find its mass in kg.

Q. One molecule of water $\left(H_{2}O\right)$ contains two atoms of hydrogen and one atom of oxygen. A hydrogen atom has a mass of $1.0u$ and an atom of oxygen has a mass of $16u$, approximately.
How many molecules of water are in the world's oceans, which have an estimated total mass of $1.4\times {10}^{21}kg$?

Q. Water is poured into a container that has a small leak. The mass $m$ of the water is given as a function of time $t$ by $m=5.00t^{0.8}-3.00t+20.00$, with $t\ge 0,m$ in grams, and $t$ in seconds.
In kilograms per minute, what is the rate of mass change at $t=2.00s$

Q. 15.Radius of He nucleus is 3 fermi. The radius of 16 S 32 nucleus will be

Q. A block of iron has dimensions $2m\times 0.5m\times 0.25m$. The density of iron is $7.8gc{m}^{-3}$ Find the mass of block.

Q. Two particles of mass $m_1$ and $m_2$ are approaching towards each other under their mutual gravitational field. If the speed of the particle is $v$, the speed of the center of mass of the system is equal to:

1. $\frac{(m_1-m_2)v}{m_1+m_2}$
2. $\frac{m_2}{m_1}v$
3. $\frac{m_1}{m_2}v$
4. zero

Q. Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii $R_1$and $R_2$, respectively. The ratio of the masses of X to that of Y is

1. $(R_1/R_2{)}^2$
2. $R_1/R_2$
3. $(R_1/R_2{)}^{1/2}$
4. $R_2/R_1$

Q. Using conversions and data in the chapter. determine the number of hydrogen atoms required to obtain $1.0kg$ of hydrogen. A hydrogen atom has a mass of $1.0u$.

Q. How are the units of weight: kgf and newton related?

Q. What is the mass of $5m^3$ of cement of density $3000kg/m^3$

Q. Which quantity : Mass or weight, does not change of place?

Q. Which of the following is the best estimate for the mass of all the people living on the Earth?

1. $2\ast {10}^{8}kg$
2. $1\ast {10}^{9}kg$
3. $3\ast {10}^{11}kg$
4. $2\ast {10}^{10}kg$
5. $4\ast {10}^{12}kg$