The question asks why Nichrome is used in electric heaters. This requires understanding the properties of materials suitable for heating elements, specifically their electrical resistance and thermal properties.
D) high resistivity and high melting point. This option correctly identifies both essential properties of Nichrome that make it suitable for electric heaters.
The problem presents a series of number pairs and asks us to find the missing number in the last pair based on the relationship observed in the previous pairs. We need to identify the pattern connecting the first number to the second number in each given pair.
Correct Option: D) 12
The question asks to identify the process that is NOT applicable to photosynthesis. We need to analyze each option in the context of the overall photosynthesis reaction and its sub-processes.
Correct Option: A) Oxidation of carbon dioxide forms carbohydrates. This statement is incorrect because carbon dioxide is reduced, not oxidized, during photosynthesis to form carbohydrates.
To find the correct balanced chemical reaction, we need to ensure that the number of atoms of each element on the reactant side (left side) is equal to the number of atoms of the same element on the product side (right side). This adheres to the Law of Conservation of Mass.
Reactants: Silver nitrate (\(\text{AgNO}_3\)), Sodium chloride (\(\text{NaCl}\))
Products: Silver chloride (\(\text{AgCl}\)), Sodium nitrate (\(\text{NaNO}_3\))
The unbalanced equation is:
\[ \text{AgNO}_3 + \text{NaCl} \rightarrow \text{AgCl} + \text{NaNO}_3 \]Let's count the atoms for each element in the unbalanced equation:
Comparing the counts, we see that the number of atoms for each element (Ag, N, O, Na, Cl) is already equal on both sides of the equation.
The given reaction is already balanced as written.
D) The equation \(\text{AgNO}_3 + \text{NaCl} \rightarrow \text{AgCl} + \text{NaNO}_3\) is already balanced, as it shows one atom of Ag, one atom of N, three atoms of O, one atom of Na, and one atom of Cl on both the reactant and product sides. This adheres to the Law of Conservation of Mass.
The question asks to identify the location of the most important Gondwana coal fields within the Jharkhand–Bengal coal belt. This requires knowledge of the major coal-producing regions in India, specifically those associated with the Gondwana rock system.
C) The Damodar Valley is the most important Gondwana coal field location within the Jharkhand–Bengal coal belt. It hosts major coalfields such as Raniganj (which extends into both states) and Jharia (in Jharkhand), making it the primary answer.
The question asks to evaluate whether the given arguments strengthen or weaken the statement about global warming. We need to analyze each argument's relevance and impact on the statement.
Correct Option: D) Both I and II strengthen the statement.
The question asks to identify the incorrect statement regarding the reactivity series of metals. We need to evaluate each option based on the properties and characteristics of the reactivity series.
Correct Option: A) Potassium is least reactive in the reactivity series. This statement is incorrect because Potassium is the most reactive metal in the series.
To determine the best material for an electromagnet, we need to consider the properties required for temporary magnetism: easy magnetization and quick demagnetization. We will evaluate the given options based on these characteristics.
A) Soft iron is the best material for making an electromagnet because it can be easily magnetized and, crucially, easily demagnetized. This allows the electromagnet to be switched on and off effectively.
Find the value of [(12 ÷\( \frac{4}{3} \)) × {6 ÷ 4 × (\(\left(\frac{12-7}{6}\right)\))} ÷ {4 × 6 ÷ 3}]
1 \( \frac{15}{32} \)
1 \( \frac{11}{32} \)
1 \( \frac{13}{32} \)
1 \( \frac{17}{32} \)
To solve this problem, we need to follow the order of operations, often remembered by the acronym BODMAS/PEMDAS (Brackets/Parentheses, Orders/Exponents, Division/Multiplication, Addition/Subtraction). We will evaluate each bracketed term separately and then combine them.
Division by a fraction is equivalent to multiplication by its reciprocal.
\[ 12 \div \frac{4}{3} = 12 \times \frac{3}{4} = \frac{36}{4} = 9 \]First, solve the innermost parenthesis:
\[ \frac{12-7}{6} = \frac{5}{6} \]Now substitute this back into the second term:
\[ 6 \div 4 \times \frac{5}{6} \]Perform division and multiplication from left to right:
\[ \frac{6}{4} \times \frac{5}{6} = \frac{3}{2} \times \frac{5}{6} = \frac{15}{12} = \frac{5}{4} \]Perform multiplication and division from left to right:
\[ 4 \times 6 \div 3 = 24 \div 3 = 8 \]The original expression is \[[ (12 \div \frac{4}{3}) \times \{6 \div 4 \times (\frac{12-7}{6})\} \div \{4 \times 6 \div 3\} ]\]
Substitute the calculated values:
\[ 9 \times \frac{5}{4} \div 8 \]Perform multiplication first:
\[ \frac{45}{4} \div 8 \]Then perform division:
\[ \frac{45}{4} \times \frac{1}{8} = \frac{45}{32} \]Convert the improper fraction to a mixed number:
\[ \frac{45}{32} = 1 \frac{13}{32} \]C) \(1 \frac{13}{32}\) is the correct answer, as derived from the step-by-step calculation.
To find the image distance formed by a convex lens, we use the lens formula, which relates the object distance, image distance, and focal length of the lens. We must also pay attention to the sign conventions for convex lenses.
The lens formula is given by:
\[ \frac{1}{f} = \frac{1}{v} - \frac{1}{u} \]The least common multiple (LCM) of 20 and 50 is 100.
\[ \frac{1}{v} = \frac{5}{100} - \frac{2}{100} \] \[ \frac{1}{v} = \frac{5 - 2}{100} \] \[ \frac{1}{v} = \frac{3}{100} \]Correct Option: A) 33.3 cm