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Q 1. If we change unit of a physical quantity then
its dimension changes.
its dimension remain same.
it may change or may not change.
its magnitude changes.
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Q 2. The least count of a stop watch is {tex}\frac{1} { 5} {/tex} s. The time of 20 oscillations of a pendulum is measured to be 25 s. The minimum percentage error in the measurement of time will be
{tex}0.1 \% {/tex}
{tex}0.8 \% {/tex}
{tex}1.8 \% {/tex}
{tex} 8\% {/tex}
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Q 3. Energy due to position of a particle is given by, {tex} U = \frac { \alpha \sqrt { y } } { y + \beta } , {/tex} where {tex} \alpha {/tex} and {tex} \beta {/tex} are constants, {tex} y {/tex} is distance. The dimensions of {tex} ( \alpha \times \beta ) {/tex} are
{tex} \left[ M ^ { 0 } L T ^ { 0 } \right] {/tex}
{tex} \left[ M ^ { 1 / 2 } L ^ { 3 / 2 } T ^ { - 2 } \right] {/tex}
{tex} \left[ M ^ { 0 } L ^ { - 7 / 2 } T ^ { 0 } \right] {/tex}
{tex} \left[ M L ^ { 7 / 2 } T ^ { - 2 } \right] {/tex}
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Q 4. A wire is of mass {tex} ( 0.3 \pm 0.003 ) {/tex} gm. The radius is {tex} ( 0.5 \pm 0.005 ) \mathrm { mm } {/tex} and length is {tex} ( 6.0 \pm 0.06 ) \mathrm { cm } {/tex} then {tex} \% {/tex} error in density is
3
4
6
- 2
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Q 5. The equation of state of some gases can be expressed as {tex} \left( P + \frac { a } { V ^ { 2 } } \right) ( V - b ) = R T . {/tex} Here, {tex} P {/tex} is the pressure, {tex} V {/tex} the volume, {tex} T {/tex} the absolute temperature, and {tex} a , b , R {/tex} are constants. The dimensions of {tex} a {/tex} are
{tex} \left[ M L ^ { 5 } T ^ { - 2 } \right] {/tex}
{tex} \left[ M L ^ { - 1 } T ^ { - 2 } \right] {/tex}
{tex} \left[ M ^ { 0 } L ^ { 3 } T ^ { 0 } \right] {/tex}
{tex} \left[ M ^ { 0 } L ^ { 6 } T ^ { 0 } \right] {/tex}
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Q 6. We have error in the measurement of length, radius, mass and current of a wire are {tex} 2 \% , 3 \% , 2 \% {/tex} and 1{tex} \% {/tex} then error in its density will be
11{tex} \% {/tex}
{tex} 8\% {/tex}
{tex}10 \% {/tex}
{tex}7 \% {/tex}
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Q 7. A physical quantity {tex} x {/tex} depends on qualities {tex} y {/tex} and {tex} z {/tex} as follows: {tex} x = A y + B {/tex} tan {tex} C z , {/tex} where {tex} A , B {/tex} and {tex} C {/tex} are constants. Which of the following do not have the same dimensions?
{tex} x {/tex} and {tex} B {/tex}
{tex} c {/tex} and {tex} z ^ { - 1 } {/tex}
{tex} y {/tex} and {tex} B / A {/tex}
{tex} x {/tex} and {tex} A {/tex}
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Q 8. The force {tex} F {/tex} is given in terms of time {tex} t {/tex} and displacement {tex} x {/tex} by the equation {tex} F = A \cos B x + C \sin D t . {/tex} The dimensions of {tex} \frac { D } { B } {/tex} are
{tex} M ^ { 0 } L ^ { 0 } T ^ { 0 } {/tex}
{tex} M ^ { 0 } L ^ { 0 } T ^ { - 1 } {/tex}
{tex} M ^ { 0 } L ^ { - 1 } T ^ { 0 } {/tex}
{tex} M ^ { 0 } L ^ { 1 } T ^ { - 1 } {/tex}
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Q 9. The diameter of a wire is measured with a screw gauge having 50 divisions on circular scale and by one complete rotation of circular scale, main scale moves {tex} 0.5 \mathrm { mm } . {/tex} If reading of screw gauge is {tex} 0.250 \mathrm { cm } . {/tex} The minimum percentage error in the reading will be
0.4
0.8
4
5
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Q 10. The length, width and thickness of a block are {tex} ( 100.0 {/tex} {tex} \pm 0.1 ) \mathrm { cm } , ( 10.00 \pm 0.01 ) \mathrm { cm } {/tex} and {tex} ( 1.000 \pm 0.001 ) \mathrm { cm } {/tex} respectively. The maximum possible error in its volume will be
{tex} \pm 0.111 \mathrm { cm } ^ { 3 } {/tex}
{tex} \pm 0.012 \mathrm { cm } ^ { 3 } {/tex}
{tex} + 0.03 \mathrm { cm } ^ { 3 } {/tex}
None of these
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Q 11. The dimensional formula of magnetic flux is
{tex} \left[ M L ^ { 2 } T ^ { - 2 } A ^ { - 1 } \right] {/tex}
{tex} \left[ M L ^ { 0 } T ^ { - 2 } A ^ { - 2 } \right] {/tex}
{tex} \left[ M ^ { 0 } L ^ { - 2 } T ^ { - 2 } A ^ { - 2 } \right] {/tex}
{tex} \left[ M L ^ { 2 } T ^ { - 1 } A ^ { 3 } \right] {/tex}
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Q 12. Error in the measurement of radius of sphere is 2{tex} \% {/tex}. Then error in the calculation of volume will be
1{tex} \% {/tex}
5{tex} \% {/tex}
3{tex} \% {/tex}
6{tex} \% {/tex}
{tex}V=\frac{4}{3}πR^33%{/tex} ∴ ,% error in {tex}V={/tex} % error in {tex}R{/tex} =3(2%)=6%.
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Q 13. The velocity of water waves may depend on their wavelength {tex} \lambda {/tex} , the density of water {tex} \rho {/tex} and the acceleration due to gravity {tex} g {/tex}. The method of dimensions gives the relation between these quantities as
{tex} v ^ { 2 } \propto \lambda g ^ { - 1 } \rho ^ { - 1 } {/tex}
{tex} v ^ { 2 } \propto g \lambda {/tex}
{tex} v ^ { 2 } \propto \lambda g \rho {/tex}
{tex} v ^ { 2 } \propto g ^ { - 1 } \lambda ^ { 2 } {/tex}
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Q 14. A dust particle oscillates in air with a time period which depends on atmospheric pressure {tex} P {/tex}, density of air {tex} d {/tex} and energy of the particle {tex} E , {/tex} then time period is proportional to
{tex} P ^ { - \frac { 5 } { 6 } } d ^ { \frac { 1 } { 2 } } E ^ { \frac { 1 } { 3 } } {/tex}
{tex} P ^ { \frac { 1 } { 2 } } d ^ { 3 } E ^ { - 2 } {/tex}
{tex} P ^ { - \frac { 1 } { 3 } } d ^ { \frac { 1 } { 2 } } E ^ { 2 } {/tex}
{tex} P ^ { - 2 } d ^ { - \frac { 1 } { 2 } } E ^ { - 3 } {/tex}
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Q 15. Which of the following group have different dimension?
Potential difference, EMF, voltage
Pressure, stress, Young's modulus
Heat, energy, work-done
Dipole moment, electric-flux, electric field
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Q 16. If a copper wire is stretched to make its radius decrease by 0.1{tex} \% {/tex}, then the percentage increase in resistance is approximately
0.1{tex} \% {/tex}
0.2{tex} \% {/tex}
0.4{tex} \% {/tex}
0.8{tex} \% {/tex}
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Q 17. Two resistances of 400 {tex}\Omega{/tex} and 800 {tex}\Omega{/tex} connected in series with a 6 volt battery of negligible internal resistance. A voltmeter of resistance 10,000 {tex}\Omega{/tex} is used to measure the potential difference across 400 {tex}\Omega{/tex}. The error in the measurement of potential difference in volts approximately is
0.01
0.02
0.04
0.05
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Q 18. If there is a positive error of 50{tex} \% {/tex} in the measurement of velocity of a body, then the error in the measurement of kinetic energy is
25{tex} \% {/tex}
50{tex} \% {/tex}
100{tex} \% {/tex}
125{tex} \% {/tex}
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Q 19. The pitch of a screw gauge is 1{tex} \mathrm { mm } {/tex} and there are 100 divisions on its circular scale. When nothing is put in between its jaws, the zero of the circular scale lies 4 divisions below the reference line. When a steel wire is placed between the jaws, two main scale divisions are clearly visible and 67 divisions on the circular scale are observed. The diameter of the wire is
2.71{tex} \mathrm { mm } {/tex}
2.67{tex} \mathrm { mm } {/tex}
2.63{tex} \mathrm { mm } {/tex}
2.65{tex} \mathrm { mm } {/tex}
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Q 20. Charge on the capacitor is given by {tex}Q=I\alpha e^{- \frac{tI}{{\triangle V}\epsilon_0\beta}}{/tex} where {tex}\alpha{/tex} and {tex}\beta{/tex} are constant, t = time, I = current, {tex} \triangle V{/tex} = Potential difference then, dimension of {tex} \frac{\beta}{\alpha}{/tex} is same as dimension of
{tex}\frac{1}{\sqrt{\mu_0 \epsilon_0}}{/tex}
{tex} \mu _ { 0 } \varepsilon _ { 0 } {/tex}
{tex} \frac { \mu _ { 0 } } { \varepsilon _ { 0 } } {/tex}
{tex} \frac { 1 } { \mu _ { 0 } \varepsilon _ { 0 } } {/tex}
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Q 21. If the speed of light {tex} ( c ) , {/tex} acceleration due to gravity {tex} ( g ) {/tex} and pressure {tex} ( p ) {/tex} are taken as fundamental units, the dimensional formula of gravitational constant {tex} ( G ) {/tex} will be
{tex} c ^ { 0 } g p ^ { - 3 } {/tex}
{tex} c ^ { 2 } g ^ { 3 } p ^ { - 2 } {/tex}
{tex} c ^ { 0 } g ^ { 2 } p ^ { - 1 } {/tex}
{tex} c ^ { 2 } g ^ { 2 } p ^ { - 2 } {/tex}
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Q 22. Energy due to position of a particle is given by, {tex} U = \frac { \alpha \sqrt { y } } { y + \beta } , {/tex} where {tex} \alpha {/tex} and {tex} \beta {/tex} are constants, {tex} y {/tex} is distance. The dimensions of {tex} ( \alpha \times \beta ) {/tex} are
{tex} \left[ M ^ { 0 } L T ^ { 0 } \right] {/tex}
{tex} \left[ M ^ { 1 / 2 } L ^ { 3 / 2 } T ^ { - 2 } \right] {/tex}
{tex} \left[ M ^ { 0 } L ^ { - 7 / 2 } T ^ { 0 } \right] {/tex}
{tex} \left[ M L ^ {5 / 2 } T ^ { - 2 } \right] {/tex}
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Q 23. Which of the following is not branch of physics?
Mechancis
Optics
Cytogenetics
Electrodynamics
Among the given branches, cytogenetics is the branch of biology.
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Q 24. Which of the following statement is correct?
Newton belonged to U.K., who discovered law of gravitation
Einstein belonged to England, who discovered laws of photoelectric effect
John Bardeen belonged to France, who discovered transistors
W.K. Roentgen belonged to Holland, who discovered X-rays
Name|Discovery|Country of Origin|
Isaac Newton|Universal law of gravitation, Laws of motion, Reflecting telescope|U.K.|
Albert Einstein|Laws of photoelectric effect, Theory of relativity|Germany |
John Bardeen|Transistors, Theory of Superconductivity|U.S.A|
W.K. Roentgen|X - rays|Germany|
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Q 25. Sir C.V. Raman got Nobel Prize in physics for
Refraction of light
Reflection of light
Scattering of light
Dispersion of light
Sir C.V. Raman got Noble prize for Raman effect, Which deals with scattering of light.