Discussion of multiple choice questons-UAD-Units and dimensions

Discussion of answers to multiple choice questions - UAD Units and Dimensions1: If the velocity of light is taken as the unit of the velocity and year as the unit of time then the unit of length will be(a)Parsec (b)Light year (c)Astronomical unit (d)None of these.2: Which of the following is the smallest unit of length ? (a)micron (b)angstrom (c)Fermi (d)parsec3: Which of the following is the largest unit of length.?(a)light year (b)par second (c)astronomical unit (d) angstrom4: If the atom were enlarged to the size of the earth how large will be the nucleus of the atom.(a)104m(b)103m (c)105m (d) 106m5: Which of the following is not the unit of a scalar quantity?(a)Kg.m.s-1 (b)Kgm2s-2 (c)Kgm2s-3 (d)Kgm2s-1 6: Which of the following pairs does not have the same dimensions?(a)impulse and momentum (b)surface energy and work(c)pressure and modulus of elasticity (d)angular momentum and linear momentum7: Which of the following pairs have the same dimensions?(a)specific heat and latent heat.(b)torque and work(d)surface tension surface energy (d)gravitational constant gravitational potential.8: Which of the following pairs has the same unit?(a)heat capacity and latent heat of fusion (b)heat capacity and specific heat capacity (c)heat capacity and entropy (d)latent heat of fusion and entropy.9: The dimensional formula MT-2 represents(a)gravitational constant (b)surface tension (c)coefficient of viscosity(d) none of these. 10: The dimension of coefficient of viscosity is (a)MLT-2 (b)ML-1T-3 (c)ML-1T-1 (d) M0L0T-211: The work done in compressing a spring through a length x is by W = 1/2kx2.The dimension of k is (a)MLT-2 (b)ML-1T-2 (c)ML0T-2 (d)MLT-112: Which of the following physical quantity has the dimensions of energy?(a)toque (b)impulse (c)angular momentum (d)stress.13: The heat generated in a circuit is dependent on the resistance, current and the time for which current is flowing. If the error in measuring the above quantities are 1%,2%,and 1% respectively, what is the maximum error in the measurement of heat if heat generated =I2Rt6% (b)4% (c)5% (d)10% 14: In an experiment the density of an object was calculated from the following measurements. Mass = 247.1 ±0.1gm , Volume = 31.66±0.04cc.The percentage error in the measurement of density will be(a)14% (b)0.14% (c)0.17% (d)1.7% 15: The initial temperature of a liquid recorded as Э1 = 25.4 ± 0.10C and on heating the final temperature is recorded as Э2 = 52.7± 0.10C.tThe increase in temperature is recorded as :(a)27.30C (b)27.50C (c)27.10C(d)27.3± 0.20C16: In an experiment the values of two resistances are measured as R1 =( 3± 0.2) ohm and R2 = (6± 0.1) ohm. If the effective resistance when they are in parallel is given by R = R1R2/(R1+R2) , then the percentage error when they are in parallel is (a)8% (b)16% (c)15%(d)12%17: The dimensional formula for a physical quantity is ML2T-3.If the errors in the measurements of M,L and T are 2%,3%,1% respectively, then the total percentage error in the measurement of the quantity is 11% (b) 6% (c) 5% (d) 14%. 18: What are the significant figures in 12.6 x 3.06 and 9546 + 1.3 (a)3 & 2 (b) 3 & 4 (c) 4 & 3 (d) 2& 3 . 19 : The order of magnitude of 4999 and 5000 are . (a)3& 4 (b) 3&3 (c) 4 & 4 (d) 2 & 3 . 20 : The order of magnitude of 500 and 5001 are . (a)4&4 (b) 3& 3 (c) 3& 4 (d) 4 & 3 . 21 : The wavelengths of red and blue light are 6563x10-10 m and 4358x10-10m respectively. The order of magnitude are . (a)-10 & -10 (b) -7 & -7 (c) -6 & -6 (d) -6 & -7 . 22 : The radius of a sphere is 2.12m , its volume in accordance with significant figure is . (a)40m3 (b) 39.9m3 (c) 39.91m3 (d) 39m3 . 23 : If the unit of force is one Kilo-Newton, unit of length is one Km and the unit of time is 100 sec. the unit of mass will be .(a)1000Kg (b) 1Kg (c) 10000Kg (d) 100gm . 24 : The value of g is 9.8ms-2 . Its value in Km/min2 is . (a)15.3 (b) 25.3 (c) 35.3 (d) 45.3 . 25: Which of the following is the largest unit?. (a)gm/cm3 (b) Kg/m3 (c) gm/litre (d) Kg/cm3 .