ICSE Class 9 Physics Workbook Solutions Hindi & English : Measurement part 4

22. Derived Units and Related Quantities

Question: Identify the physical quantities associated with the following derived units.

Answer:

(a) Joule: Energy or Work

(जूल): ऊर्जा या कार्य

(b) Newton: Force

(न्यूटन): बल

(c) Pascal: Pressure

(पास्कल): दबाव

(d) Hertz: Frequency

(हर्ट्ज): आवृत्ति

(e) Watt: Power

(वाट): शक्ति

(f) Coulomb: Electric Charge

(कूलम्ब): विद्युत आवेश

(g) Day: Time

(दिन): समय

23. Symbols for Units

Question: Write symbols for the following units.

Answer:

(a) Ampere: A

(एम्पीयर): A

(b) Kelvin: K

(केल्विन): K

(c) Candela: cd

(कैंडेला): cd

(d) Newton: N

(न्यूटन): N

(e) Joule: J

(जूल): J

(f) Watt: W

(वाट): W

24. Named Derived Units

Question: Can you provide two examples of derived units that are named after scientists?

Answer:

(1) Joule (after James Prescott Joule)

(2) Newton (after Sir Isaac Newton)

(2) न्यूटन (सर आइज़क न्यूटन के नाम पर)

Question: How are these units related to fundamental units in the S.I. system?

Answer:

(1) Joule: Defined as the work done when a force of one newton moves an object one meter.

1 J = 1 kg * m²/s²

(1) जूल: यह उस कार्य को परिभाषित करता है जो एक न्यूटन बल द्वारा एक मीटर की दूरी पर किया जाता है।

1 J = 1 किलोग्राम * मीटर²/सेकंड²

(2) Newton: The force needed to accelerate one kilogram at one meter per second squared.

1 N = 1 kg * m/s²

(2) न्यूटन: एक किलोग्राम के द्रव्यमान को एक मीटर प्रति सेकंड के वर्ग में त्वरित करने के लिए आवश्यक बल।

1 N = 1 किलोग्राम * मीटर/सेकंड²

Question: Write down the derived unit of the following physical quantities.

Answer:

(a) Force: Newton (N)

(a) बल: न्यूटन (N)

(b) Work: Joule (J)

(b) कार्य: जूल (J)

(c) Power: Watt (W)

(c) शक्ति: वाट (W)

(d) Pressure: Pascal (Pa)

(d) दबाव: पास्कल (Pa)

(e) Electrical potential: Volt (V)

(e) विद्युत विभव: वोल्ट (V)

(f) Electrical resistance: Ohm (Ω)

(f) विद्युत प्रतिरोध: ओम (Ω)

True/False Statements

Question: statements are true or false.

Answer:

(a) False (Newton is a derived unit)

(a) गलत (न्यूटन एक व्युत्पन्न इकाई है)

(b) False (Angstrom is a unit of length)

(b) गलत (एंगस्ट्रॉम लंबाई की इकाई है)

(c) True (Symbol of watt is W)

(c) सही (वाट का प्रतीक W है)

(d) True (1 Joule = kg m² s⁻²)

(d) सही (1 जूल = kg m² s⁻² है)

(e) True (Increasing order: A.U. < ly < parsec)

(e) सही (वृद्धि क्रम: A.U. < ly < पार्सेक)

(f) False (2100 is not a leap year)

(f) गलत (2100 लीप वर्ष नहीं है)

English): What does the term “least count” refer to in the context of measuring instruments?

Answer (English): The term “least count” refers to the smallest value or increment that can be measured accurately by a measuring instrument. It indicates the precision and resolution of the instrument, determining how finely measurements can be taken.

Question: Name three instruments used to measure length, in increasing order of accuracy.

Answer:

(1) Measuring Tape

(1) मापन टेप

(2) Metre Rule

(2) मीटर रूल

(3) Vernier Callipers

(3) वर्नियर कैलीपर्स

Question: Write the approximate least count of the following:

Answer:

(i) Metre rule: 1 cm (10 mm)

(i) मीटर रूल: 1 सेंटीमीटर (10 मिमी)

(ii) Vernier callipers: 0.01 cm (0.1 mm)

(ii) वर्नियर कैलीपर्स: 0.01 सेंटीमीटर (0.1 मिमी)

(iii) Screw gauge: 0.001 cm (0.01 mm)

(iii) स्क्रू गेज: 0.001 सेंटीमीटर (0.01 मिमी)

29. Vernier Constant

(a) What is meant by vernier constant?

The vernier constant is the difference in length between one main scale division and one vernier scale division. It helps determine how precise the vernier callipers are.

(वर्नियर स्थिरांक): वर्नियर स्थिरांक मुख्य पैमाने के एक विभाजन और वर्नियर पैमाने के एक विभाजन के बीच की लंबाई का अंतर है। यह वर्नियर कैलीपर्स की सटीकता को निर्धारित करने में मदद करता है।

Question: Write down the formula for finding the least count of a vernier callipers.

Answer:

Least Count=Value of the Most Significant Digit (MSD)−Value of the Least Significant Digit (VSD)

(कम से कम गणना का सूत्र):

Question: Name the two scales of a vernier callipers.

Answer:

Main Scale (MS)

(मुख्य पैमाना): MS

Vernier Scale (VS)

(वर्नियर पैमाना): VS

30-31. Vernier Callipers

Question: A vernier callipers has its main scale graduated in mm, and there are 10 divisions on its vernier scale. 

Find:

(You would typically perform a calculation here based on the details of the scales.)

Question: Write down (a) the least count and (b) the reading of the vernier callipers in the adjacent diagram.

Answer:

(a) Least count: 

(b) Reading:

Physics Workbook Solutions Hindi and English : Part 2 ( Q 7 to 15 ) ICSE Class 9

Part 3 workbook solution icse physics class 9

Part 1 workbook solution icse physics class 9

Physics Workbook Solutions Hindi and English : Part 3 ( Q 16 to 21 ) ICSE Class 9