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[ Exercise - | I, , SECTION A: UNITS, 1. Which of the following is not the name of a physical, quantity ?, , (A) kilogram (B) impulse, © energy (D) density, , 2. Light year is the unit of, , (A) speed (B) mass, (C) distance (D) time, Sol., , 3. PARSEC is a unit of, , (A) Time (B) Angle, (C) Distance (D) Velocity, Sol., , 4. Which of the following system of units is NOT based, on the unit of mass, length and time alone, , (A) FPS (B) SI, (C) ces (D) MKS, Sol., , 5. In the S.I. system the unit of energy is(A) erg (B) calorie, (C) joule (D) electron volt, , I, , OBJECTIVE PROBLEMS (JEE MAIN), , UNITS AND DIMENSIONS, , ], , Sol., , 6. Unit of pressure in S.1. system is, (A) atmosphere (B) dynes per square cm, (C) pascal (D) bar, Sol., , 7eIn Slunit the angular acceleration has unit of(A) Nmkg? ~~ (B) ms?, (C)rad.s? (D) Nkg?, , Sol., , 8. The SI unit of the universal gravitational constant, , Gis, , (A) Nm kg? (B) NrPkg?, (C) Nm? kg (D) Nmkg*, Sol., , 9. Surface tension has unit of(A) Joule.m? (B) Joule.m?, (C) Joule.m (D) Joule.m?
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10. The unit of intensity of magnetisation is, (A) Amp m? (B) Amp m?, (C) Amp m (D) Amp mt, Sol., 11. The M.K.S. units of coefficient of viscosity is(A) kg mts? (B) kgms?, (C) kg m? s* (D) kg? m* s?, Sol., , 12. The specific resistance has the unit of, (A) ohm/m (B) ohm/n, (C) ohm. (D) ohm.m, Sol., , 13. The mutual inductance has unit of(A) Gauss (B) Weber, , (C) Farad (D) Henry, , Sol., , , , 14. The unit of magnetic moment is, (A) amp nm’ (B) amp m?, (C)ampm (0) amp m*, Sol., , 15. The SI unit of the universal gas constant R is :, , (A) erg K mol"! (B) watt K-! mol-*, (C) newton K-* mol-* (0) joule K* mol, Sol., , 16. A physical quantity is measured and the result is, expressed as nu where u is the unit used and nis the, numerical value. If the result is expressed in various, Units then, , (A) n « size of u (B)n xu?, (C)nx vu (D)n«1/u, Sol., , 17. One watt-hour is equivalent to, , (A) 6.3 x 10? Joule (B) 6.3 x 10-7 Joule, (C) 3.6 x 10? Joule (D) 3.6 x 10°? Joule, Sol.
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18. Which of the following statement is wrong ?, (A) Unit of K.E. is Newton-metre, , (B) Unit of viscosity is poise, , (C) Work and energy have same dimensions, , (D) Unit of surface tension is Newton metre, Sol., , SECTION : B DIMENSIONS, , 19. What are the dimensions of lenth in force x, displacement/time, (A) -2 (B)0, ‘Sol, , (C)2 (D) none of these, , 20. The angular frequency is measured in rad s“'. Its, dimension in length are:, (A)-2 9 (B)-1, , Sol., , (C)o (D)2, , 21 [MLT™] are the dimensions of(A) power (B) momentum, (C) force (D) couple, , Sol., , 22. The dimensional formula for angular momentum, is, (A) MUT?, (C) MLT”, , (B) MUT", (D) M°L7T?, , , , , , 23. The dimensions of universal gravitational constant, are, , (A) MDT? (By MPT, (C) M7 Lt T? (D) M2? UT?, Sol., , 24. The SI unit of Stefan's constant is :, , (A) Ws" m-? K+ (B) J sm?! kK", (C)d's! m? K+ (D) Wm? K+, Sol., , 25. What are the dimensions of Boltzmann's constant?, , (A) MLT?K"! (8) MLTK*, (C) MeLT=2 (D) ML-T?K-!, Sol., , 26. Dimensions of magnetic flux density is (A) MEL? THAD (B) ML’ T?A", (C) MPL! T?A7 (D) M* L° THA?
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UNITS AND DIMENSIONS, , 27. A pair of physical quantities having the same, dimensional formula is :, , (A) angular momentum and torque, , (B) torque and energy, , (C) force and power, , (D) power and angular momentum, , 28. Dimensions of pressure are the same as that of, (A) force per unit volume, , (B) energy per unit volume, , (C) force, , (D) energy, , 29. Which one of the following has the dimensions of, ML“T-??, , (A) torque, (C) viscosity, , (B) surface tension, (D) stress, , , , 30. The dimensions of the quantity aay are, (A) M° L? TIA! (B) M?L? TA, (C) M° L? TPA! (D) M® L? TA, Sol., , 31. For 10-») , the dimension of a is, (A) M° L? T? (B) M°L? T*, (C) M?L? T* (D) None of these, Sol., , 32. The pressure of 10° dyne/cm? Is equivalent to, (A),105 N/m? (B) 10° N/m?, (C).10” N/m? (D) 10 N/m?, , 33. The SI unit of length is the meter. Suppose we, adopt a new unit of length which equals to, , x meters. The area 1m2 expressed in terms of the, new unit has a magnitude, (A) x (8), , 1 1, () x (0), Sol., , 34. p = 2. g/cm? convert it into MKS system , (A) 2 x 109 #2 (8)2 x 10 *8, (c) 4x 10" (0) 2 x 10 *S, , Sol.
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UNITS AND DIMENSION:, , , , 35. Given that v Is the speed, r is radius and g is, acceleration due to gravity. Which of the following is, dimension less, , v3 v, (a) 38 (8) v'rg (2) 5, Sol., , (C) veg, , 36. Choose the correct statement(s) :, , (A) A dimensionally correct equation must be correct., (B) A dimensionally correct equation may be correct., (C) A dimensionally incorrect equation may be correct., (D) A dimensionally incorrect equation may be, incorrect., , Sol., , 37. The value of G = 6.67 x 10°! N m? (kg)-?. Its, numerical value in CGS system will be :, , (A) 6.67 x 10° (B) 6.67 x 10°, , (C) 6.67 (D) 6.67 x 10-5, , Sol., , , , 38. The density of mercury Is 13600 kg rm’. Its value, of CGS system will be :, , (A) 13.6 g cm? (B) 1360 g cm?, (C) 136 g cm? (D) 1.36 g cm?, Sol., , BASIC MATHEMATICS, , 39. The radius of two circles are rand 4r what will be, the ratio of their-Area and perimeter., Sol., , 40. Internal radius of a ball is 3 cm and external radius, is 4cm. What will be the volume of the material used., Sol.
