The document Basic Mathematics and Measurement(Part- 1) - Physics, Solution by DC Pandey NEET Notes | EduRev is a part of the NEET Course DC Pandey Solutions for JEE Physics.

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**Single Correct Option**

**Q.1. Percentage error in the measurement of mass and speed are 2% and 3% respectively. The error in the estimate of kinetic energy obtained by measuring mass and speed will be (a) 12% (b) 10% (c) 8% (d) 2%**

âˆ´

âˆ´ Maximum error = 2% + 2 (3%)

In the estimate of, kinetic energy (K) = 8%

Option (c) is correct.

= 4% + 3(3%)

= 13%

Option (d) is correct.

âˆ´ Permissible error in pressure (p)

= 4% + 2 (2%)

= 8%

Option (a) is correct.

â‡’

âˆ´ Percentage increase in pressure = 100/9

= 11.1

Option (a) is correct.

âˆ´ Error in the measurement of kinetic energy (K)

= 2 x 100%

= 200%

Option (d) is correct.

3400 = 3.400 x 10

âˆ´ Number of significant figures = 2

Option (d) is correct.

A = 3.124 m x 3.002 m

= 9.378/248 m

= 9.378 m

Option (a) is correct.

âˆ´ Decrease in R (radius) by 2% world increase g by 4% and decrease K (rotational kinetic energy) by 4%.

Option (b) is correct.**Q.9. The heat generated in a circuit is dependent upon the resistance, current and time for which the current is flown. If the error in measuring the above are 1%, 2% and 1% respectively. The maximum error in measuring the heat is ****(a) 8% ****(b) 6% ****(c) 18% ****(d) 12%****Ans.** (b)** ****Solution.**

Heat (H) = I^{2} Rt

âˆ´ Maximum error in measuring heat (H)

=2 (2%) + 1% + 1%

= 6%

Option (b) is correct.**Q.10. ****The length, breadth and thickness of a block are given by / = 12 cm, b = 6 cm and t =2.45 cm. The volume of the block according to the idea of significant figures should be (a) 1 x 10 ^{2} cm^{3} (b) 2 x 10^{2} cm^{3} (c) 1.763 x 10^{2} cm^{3} (d) None of these**

V = lbt

Option (b) is correct.

i.e., Ir

i.e., if 'r' is increased by 2%,

the intensity will decrease by 4%.

Option (d) is correct.

Option (b) is correct.

= 3(1%)

= 3%

Option (c) is correct.

a

âˆ´ a = 6

â‡’ V = 6

Option (b) is correct.

Option (a) is correct.

**Solution. **

(given)

We know that

Q = It

â‡’

Option (a) is correct.**Q.17. A physical quantity A is dependent on other four physical quantities p, q, r and s as given by ****The percentage error of measurement in p , q , r and s are 1%, 3%, 0.5% and 0.33% respectively, then the maximum percentage error in A is****(a) 2% (b) 0% (c) 4% (d) 3%**

Option (c) is correct.

= 2mm/4 = 0.5 mm

= 0.1 mm Zero error = - 30 x 0.01 mm = -0.3 mm

(â€“ive sign, zero of circular scale is lying above observed reading of plate thick)

= 2 MSR + 20 CSR

= (2 Ã— 0.5 mm) + (20 Ã— 0.01 mm) = 1 mm + 0.2 mm = 1.2 mm.

Plate thickness (corrected reading)

= observed reading - zero error = 1.2 mm + 0.3 mm = 1.5 mm

Option (d) is correct.

**More than One Correct Options**

**Q.1. Given, If the percentage errors in a, b and c are + 1%, Â± 4% and + 2% respectively. ****(a) The percentage error in x can be +13%****(b) The percentage error in x can be +7% ****(c) The percentage error in x can be +18% ****(d) The percentage error in x can be +19%****Ans. (a, b)****Solution. **

Maximum percentage error in x:

= 1 (% error in a) + 2 (% error in b) +3 (% error in c)

= 15%

**Assertion and Reason**

**Directions: Choose the correct option. ****(a) If both Assertion and Reason are true and the Reason is correct explanation of the Assertion. ****(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion. ****(c) If Assertion is true, but the Reason is false. ****(d) If Assertion is false but the Reason is true.****Assertion: ****A screw gauge having a smaller value of pitch has greater accuracy.Reason: The least count of screw gauge is directly proportional to the number of divisions on circular scale.**

â–º Least count of screw gauge

â–º Less the value of pitch, less will be least count of screw gauge leading to len uncertainty that is more accuracy in the measurement.

Thus, assertion is true.

â–º From the above relation we conclude that least count of screw gauge is inversely proportional to the number of divisions of circular scale.

Thus reason is false.

Option (c) is correct.

**Match the Columns**

**Q.1. Match the following two columns.**

**Ans. ** (a) â†’ q (b) â†’ r (c) â†’ r (d) â†’ r**Solution.****(d) **

â‡’

= [L^{2} T^{â€“2}]

âˆ´ (d) â†’ (r)

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