Quiz , Units and Dimensions

QUIZ TEST – I

Question :1  [ML-1T-2] is the dimensional formula of

(A) force

(B) coefficient of friction

(C) modulus of elasticity

(D) energy

Click to See Answer :
Ans: (C)

 

Question :2 The dimensional formula of coefficient of viscosity is

(A) [MLT-1]

(B) [M-1L2T-2]

(C) [ML-1T -1]

(D) none of these

Click to See Answer :
Ans: (C)

 

Question :3 On the basis of dimensional equation, the maximum number of unknown that can be found, is

(A) one

(B) two

(C) three

(D) four

Click to See Answer :
Ans: (C)

 

Question :4 If v stands for velocity of sound, E is elasticity and d the density, then find x in the equation v = (d/E)x

(A) 1

(B) ½

(C) 2

(D) -1/2

Click to See Answer :
Ans: (D)

 

Question :5 The multiplication of 10.610 with 0.210 upto correct number of significant figure is

(A) 2.2281

(B) 2.228

(C) 2.22

(D) 2.2

Click to See Answer :
Ans: (B)

 

Question :6  The measurement of radius of a circle has error of 1%. The error in measurement of its area is

(A) 1%

(B) 2%

(C) 3%

(D) none of these

Click to See Answer :
Ans: (B)

 

Question :7 Dimensional formula of latent heat

(A) M0L2T-2

(B) MLT-2

(C) ML2T-2

(D) ML2T-2

Click to See Answer :
Ans: (A)

 

Question :8  In case of measurement of ‘g’, if error in measurement of length of pendulum is 2%, the percentage error in time period is 1 %. The maximum error in measurement of g is

(A) 1 %

(B) 2 %

(C) 4 %

(D) no error

Click to See Answer :
Ans: (C)

 

Question :9 If length of pendulum is increased by 2%. The time period will

(A) increases by 1%

(B) decreases by 1%

(C) increases by 2%

(D) decreases by 2%

Click to See Answer :
Ans: (A)

 

Question :10  If radian correction is not considered in specific heat measurement. The measured value of specific heat will be

(A) more than its actual value.

(B) less than its actual value.

(C) remains same as actual value.

(D) none of these.

Click to See Answer :
Ans: (A)

 

Question :11 The S.I. unit of universal gas constant is

(A) Watt K-1mol-1

(B) N K-1mol-1

(C) J K-1mol-1

(D) erg K-1mol-1

Click to See Answer :
Ans: (C)

 

Question :12  The dimensional formula of couple

(A) ML2T-2

(B)MLT-1

(C) ML-1T-1

(D) M1L1T-2

Click to See Answer :
Ans: (A)

 

Question :13 An experiment measures quantities a, b, c and x is calculated from $ \displaystyle x = \frac{a b^2}{c^3} $ . If the maximum percentage error in a, b and c are 1%, 3% and 2% respectively, the maximum percentage error in x will be

(A) 13%

(B) 17%

(C) 14%

(D) 11%

Click to See Answer :
Ans: (A)

 

Question :14 Dimensional formula of thermal conductivity is

(A) ML2T -3θ-1

(B) ML2T -2θ-4

(C) ML2T -2θ-1

(D) MLT -3θ-1

Click to See Answer :
Ans: (D)

 

Question :15  Three measurements 7.1 J , 7.2 J and 6.7 J are made as experiment the result with correct number of significant figures is

(A) 7.1 J

(B) 7.06 J

(C) 7.0 J

(D) 7 J

Click to See Answer :
Ans: (C)

 

Question :16  If P represents radiation pressure, c represents speed of light and Q represents radiation energy striking a unit area per second, then non-zero integers x, y and z, such that PxQycz is dimensionless, may be

(A) x = 1, y =1, z = 1.

(B) x = 1, y =-1, z = 1.

(C) x = -1, y =1, z = 1.

(D) x = 1, y = 1, z = 1

Click to See Answer :
Ans: (B)

 

Question :17  A spherical ball of mass m and radius r is allowed to fall in a medium of viscosity η. The time in which the velocity of the body increases from zero to 0.63 times the terminal velocity is called time constant (τ). Dimensionally τ can be represented by

(A)$ \displaystyle \frac{m r^2}{6 \pi \eta} $

(B)$ \displaystyle \sqrt{\frac{6 \pi m r \eta}{g^2}} $

(C) $ \displaystyle \frac{m }{6 \pi \eta r } $

(D) none of these.

Click to See Answer :
Ans: (C)

 

Question :18 Which of the following is a possible dimensionless quantity ?

(A) Velocity gradient

(B) Pressure gradient

(C) Displacement gradient

(D) Force gradient

Click to See Answer :
Ans: (C)

 

Question :19 In specific resistance measurement of a wire using a meter bridge, the key k in the main circuit is kept open when we are not taking readings. The reason is

(A) the emf of cell will decrease.

(B) the value of resistance will change due to joule heating effect.

(C) the galvanometer will stop working.

(D) none of these.

Click to See Answer :
Ans: (B)

 

Question :20 In the experiment of verification of Ohm’s law the error in the current measurement is 1%, while that in the voltage measurement is 2%. The error in the resistance has a maximum value of

(A)1%

(B) 2%

(C) 3%

(D) none of these.

Click to See Answer :
Ans: (C)

 

Click to See All Answers :
1.C   2. C   3. C   4. D   5. B   6. B   7. A   8 C   9. A   10. A  

ANSWER:

11. C   12. A   13. A   14. D   15. C   16 B   17. C   18. C   19. B   20. C  

 




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