131. वाग्यक्ति (Q), बिशिष्ट तापधारण शक्ति (S) तापक्ममा भएको परिवर्तन (dt) दिइएको अय स्पामा पिण्ड निकाल्ने सूत्र कुन सही छ?

If heat energy [tex]\((Q)\)[/tex], specific heat capacity [tex]\((S)\)[/tex], and change in temperature [tex]\((dt)\)[/tex] are given, then which of the following formulas is correct to calculate mass?

(i) [tex]\( m = \frac{S \cdot dt}{Q} \)[/tex]
(ii) [tex]\( m = \frac{Q \times dt}{S} \)[/tex]
(iii) [tex]\( m = \frac{dt}{Q \times S} \)[/tex]
(iv) [tex]\( m = \frac{Q}{S \cdot dt} \)[/tex]

(e) तलका मध्ये कुन अवस्थामा जम्मा इलेक्ट्रोनको संख्या 10 हुन्छ?

In which of the following conditions is the total number of electrons 10?

(i) [tex]\( O^- \)[/tex]
(ii) [tex]\( Mg \)[/tex]
(iii) [tex]\( Na^+ \)[/tex]
(iv) [tex]\( N^- \)[/tex]

(1) दिइएको संरचना साथको सही आणविक सूत्र कुन हो?

Which of the following is the correct molecular formula for the given structural formula?

(i) [tex]\( C_3H_6(OH)_2 \)[/tex]
(ii) [tex]\( C_3H_5(OH)^n \)[/tex]
(iv) [tex]\( C_3H_2(OH_2)_3 \)[/tex]

चितमा दिइएका मध्ये B अवस्थाको मौरो 5.5 दिनमा प्युपा अवस्थामा परिणत भयो भने उक्त मौरो कुन प्रकारको मौरी बन्न सक्छ?

In the figure, if the bee of condition B is converted to a pupa in 5.5 days, which type of honey bee can it form?

(i) कर्मी मौरी (worker bee)
(ii) भाले मौरी (drone bee)
(iii) रानी मौरी (queen bee)
(iv) रानी र कर्मी मौरी (queen and worker bee)

(h) दुई वस्तुको पिण्डलाई समान राखी ती दुई वस्तुबिचको दूरी दोब्बर गर्दा उक्त वस्तुमा उत्पन्न हुने गुरुत्वाकर्षण बल कति होला?

Keeping the mass of two bodies constant, the distance between them is doubled. What will be the gravitational force exerted between them?

(i) [tex]\( F = G \frac{m_1 \cdot m_2}{d^2} N \)[/tex]
(ii) [tex]\( F = G \frac{m_1 m_2}{2d^2} N \)[/tex]
(iii) [tex]\( F = 2G \frac{m_1 \cdot m_2}{d^2} N \)[/tex]
(iv) [tex]\( F = G \frac{m_1 \cdot m_2}{4d^2} N \)[/tex]



Answer :

Let's break down the given physics questions and provide detailed, step-by-step solutions.

### Question 1:
Given:
- Heat energy, [tex]\( Q \)[/tex]
- Specific heat capacity, [tex]\( S \)[/tex]
- Change in temperature, [tex]\( dt \)[/tex]

Which of the following formulas is correct to calculate mass, [tex]\( m \)[/tex]?
(i) [tex]\( m = \frac{S \times dt}{Q} \)[/tex]
(ii) [tex]\( m = \frac{Q \times dt}{S} \)[/tex]
(iii) [tex]\( m = \frac{dt}{Q \times S} \)[/tex]
(iv) [tex]\( m = \frac{Q}{S \times dt} \)[/tex]

#### Solution:
The relationship between heat energy, specific heat capacity, mass, and change in temperature is given by:
[tex]\[ Q = m \times S \times dt \][/tex]

Rearranging to solve for mass [tex]\(m\)[/tex]:
[tex]\[ m = \frac{Q}{S \times dt} \][/tex]

Therefore, the correct formula to calculate the mass [tex]\( m \)[/tex] is:
(iv) [tex]\( m = \frac{Q}{S \times dt} \)[/tex]

### Question 2:
In which of the following conditions is the total number of electrons 10?
(i) [tex]\( O^{-} \)[/tex]
(ii) [tex]\( Mg \)[/tex]
(iii) [tex]\( Na^{+} \)[/tex]
(iv) [tex]\( N^{-} \)[/tex]

#### Solution:
- For [tex]\( O^{-} \)[/tex]: Oxygen has 8 protons (atomic number 8) and gains 1 electron to become [tex]\( O^{-} \)[/tex]. So, the number of electrons = 8 + 1 = 9.
- For [tex]\( Mg \)[/tex]: Magnesium has 12 protons (atomic number 12). If it is neutral, the number of electrons = 12.
- For [tex]\( Na^{+} \)[/tex]: Sodium has 11 protons (atomic number 11) and loses 1 electron to become [tex]\( Na^{+} \)[/tex]. So, the number of electrons = 11 - 1 = 10.
- For [tex]\( N^{-} \)[/tex]: Nitrogen has 7 protons (atomic number 7) and gains 1 electron to become [tex]\( N^{-} \)[/tex]. So, the number of electrons = 7 + 1 = 8.

Therefore, the correct condition where the total number of electrons is 10 is:
(iii) [tex]\( Na^{+} \)[/tex]

### Question 3:
Which of the following is the correct molecular formula for the given structural formula?
(i) [tex]\( C_3H_6(OH)_2 \)[/tex]
(ii) [tex]\( C_3H_5(OH)_3 \)[/tex]
(iii) [tex]\( C_3H_2(OH)_2 \)[/tex]
(iv) None of the above

#### Solution:
To verify the correct molecular formula, we must match the structural formula with the correct option:

- [tex]\( C_3H_6(OH)_2 \)[/tex]: This implies the molecule has 3 carbon atoms, 6 hydrogen atoms, and 2 hydroxyl groups (-OH).
- [tex]\( C_3H_5(OH)_3 \)[/tex]: This implies 3 carbon atoms, 5 hydrogen atoms, and 3 hydroxyl groups.
- [tex]\( C_3H_2(OH)_2 \)[/tex]: This implies 3 carbon atoms, 2 hydrogen atoms, and 2 hydroxyl groups.

Based on typical organic chemical structures, and without the actual structure being provided here, the most standard matching options would be:
(i) [tex]\( C_3H_6(OH)_2 \)[/tex]

### Question 4:
In the figure, the bee of condition B is converted to pupa in 5.5 days. Which type of honey bee can it form?
(i) Worker bee
(ii) Drone bee
(iii) Queen bee
(iv) Queen and worker bee

#### Solution:
- Worker bees are usually female and non-reproductive, with developmental periods generally ranging around 21 days.
- Drone bees are male and develop in about 24 days.
- Queen bees, which are reproductive females, develop in the shortest period, typically around 16 days.

Given that the bee in condition B is converted to a pupa in 5.5 days, this matches the developmental period typical for:
(iii) Queen bee

### Question 5:
When the mass of two bodies remains constant, and the distance between them is doubled, what will be the gravitational force exerted between them?
(i) [tex]\( F = G \frac{m_1 \cdot m_2}{d^2} \)[/tex]
(ii) [tex]\( F = G \frac{m_1 \cdot m_2}{2d^2} \)[/tex]
(iii) [tex]\( F = 2G \frac{m_1 \cdot m_2}{d^2} \)[/tex]
(iv) [tex]\( F = G \frac{m_1 \cdot m_2}{4d^2} \)[/tex]

#### Solution:
The gravitational force between two bodies is given by Newton's law of gravitation:
[tex]\[ F = G \frac{m_1 \cdot m_2}{d^2} \][/tex]

If the distance [tex]\( d \)[/tex] is doubled, the new distance becomes [tex]\( 2d \)[/tex]. The new force [tex]\( F_{\text{new}} \)[/tex] is:
[tex]\[ F_{\text{new}} = G \frac{m_1 \cdot m_2}{(2d)^2} = G \frac{m_1 \cdot m_2}{4d^2} \][/tex]

Therefore, the gravitational force becomes one-fourth of its original value:
(iv) [tex]\( F = G \frac{m_1 \cdot m_2}{4d^2} \)[/tex]