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\lambda = 1 m; v = 200 ms\(^{-1}\); f = ?; f = \(\frac{\text{v}{ \lambda}\) = \(\frac{200}{1}\) = 200 Hz

1a. Tables of values M(g) W\(_1\)(g) W\(_2\)(g) W\(_3\)(g) U = (W\(_1\) - W\(_2\)(g) V = (W\(_1\) - W\(_3\)(g) 5.0 5.00 4.20 4.70 0.80 0.30 10.0 10.00 7.90 8.60 2.10 1.40 15.0 15.00 12.75 13.50 2.25 1.50 20.0 17.10 17.10 16.40 2.90 3.60 25.0 22.10 22.10 21.40 2.90 3.60 S = \(\frac{y_2 - y_1}{x_2 - x_1}\) = \(\frac{3 - 0.8}{2.8 - 1.4}\) = \(\frac{11}{7}\) = 1.57. Precaution (i) I carefully avoided parallax error while reading the scale of the spring balance to ensure accurate measurements. (ii) I checked and accounted for any zero error on the spring balance before taking measurements. (iii) I handled the liquid carefully to prevent any splashing, which could lead to loss of material or inaccurate readings. (iv) I ensured that the object did not touch the bottom or sides of the beaker to avoid interference with the force readings. (v) I thoroughly cleaned the object (mass) before dipping it into the liquid to prevent contamination or alteration of the liquid's properties. bii) Law of Floatation: The law of floatation states that an object will float in a fluid if its weight is equal to the weight of the fluid it displaces. For a floating object, the weight of the object is balanced by the upward buoyant force.

2a. Table of observations D(cm) D\(^2\)(cm\^2\) X\(_1\)(cm) L = (X\(_1 - X_2\)) L\(^2\)(cm\(^2\)) 100 10000 80.50 62.20 3868.8 90 8100 70.20 51.20 2621.4 80 6400 59.10 39.10 1528.8 70 4900 46.70 24.70 610.09 60 3600 29.00 21.40 457.96 S = \(\frac{y_2 - y_1}{x_2 - x_1}\) = \(\frac{6250 - 3250}{100 - 60}\) = \(\frac{3000}{40}\) = 75 K = \(\frac{\text{s}}{4}\) = \(\frac{75}{4}\) = 18.75 Precautions: (i) I carefully avoided parallax error by ensuring my eyes were directly in line with the markings on the metre rule while taking measurements to improve accuracy. (ii) I adjusted the setup and focused precisely to ensure a sharp and well-defined image was formed on the screen, minimizing errors due to blurriness or misalignment. (iii) I made sure that the experimental apparatus was stable and free from vibrations to avoid any disturbance during measurements. (iv) I ensured that the metre rule was properly calibrated and positioned perpendicular to the setup to prevent measurement inaccuracies due to angle errors. bi. A real image is formed when light rays converge and meet at a point, allowing it to be projected onto a screen. It is typically inverted relative to the object, as seen in concave mirrors or convex lenses when the object is beyond the focal point. On the other hand, a virtual image is formed when light rays appear to diverge from a point but do not actually meet. This type of image cannot be projected onto a screen and is always upright, as seen in plane mirrors or convex mirrors. bii. See diagram above.

Downward delivery (also known as upward displacement of air) is a method used to collect gases that are denser than air. Air has an average relative molecular mass of approximately 29. CO (Carbon Monoxide) has a molecular mass of 28, making it slightly lighter than air. N\(_2\) (Nitrogen) has a molecular mass of 28, making it slightly lighter than air. Because both gases in this pair are lighter than air, they will rise rather than settle at the bottom of a gas jar, meaning they cannot be collected by downward delivery.

Nickel acts as a catalyst in the hydrogenation of alkenes. Catalysts function by providing an alternative reaction pathway with a lower activation energy. By lowering the energy barrier, a larger fraction of reactant molecules have sufficient energy to react at a given temperature, which significantly increases the reaction rate. In this specific reaction, nickel adsorbs hydrogen onto its surface, weakening the H-H bonds and facilitating their addition to the alkene.

Aluminum is a highly reactive metal, placing it high on the reactivity series. Because it forms very stable oxides, it cannot be extracted from its ore (bauxite) using standard chemical reducing agents like carbon or coke. Instead, the industrial extraction process is by electrolysis of the purified ore.

Carbon(IV)oxide, commonly known as carbon dioxide (CO\(_2\)), is the primary gas used in fire extinguishers because it is non-combustible and denser than air. When released, it displaces the oxygen surrounding the fire, effectively "suffocating" the flames by removing one of the three essential components (fuel, heat, and oxygen) needed for combustion.

Sodium (Na\(^+\)) and potassium (K\(^+\)) are cations, meaning they have already lost an electron to achieve a stable noble gas configuration. Because they are positively charged, they have a tendency to accept electrons to return to their neutral elemental state (Na or K), a process called reduction. Conversely, option A, which is the tendency to give electrons describes the neutral atoms (Na and K) which are strong reducing agents that readily lose their single valence electron. Once they become Na\(^+\) and K\(^+\) ions, they have a stable octet and do not tend to lose further electrons. The correct answer is option C.

To determine the correct conditions, we use the Combined Gas Law, which relates the pressure, volume, and temperature of a fixed amount of gas: \(\frac{P\(_1\)V\(_1\)}{T\(_1\)}\) = \(\frac{P\(_2\)V\(_2\)}{T\(_2\)}\) Given: V\(_1\) = 400 cm\(^3\) , T\(_1\) = 400 K , P\(_1\) = 1 atm V\(_2\) = 200 cm\(^3\) , T\(_2\) = ? , P\(_2\) = ? We need to find which pair of pressure and temperature satisfies the equality P\(_1\)V\(_1\)/T\(_1\) = P\(_2\)V\(_2\)/T\(_2\) First, calculate the initial constant: \(\frac{1 atm . 400cm{^3}}{400K}\) = 1 Now, test Option C: P\(_2\) = 1 atm V\(_2\) = 200cm\(^3\) T\(_2\) = 200 K \(\frac{1 atm . 200cm{^3}}{200K}\) = 1 Options A, B and D will not give you 1.

The nucleus of an ordinary hydrogen atom (specifically the most abundant isotope, protium) consists of a single proton. Atomic Number: Hydrogen has an atomic number of 1, meaning it contains exactly one proton.

Acidified potassium dichromate (K\(_2\)Cr\(_2\)O\(_7\)) is a strong oxidizing agent that undergoes a distinct colour change during redox reactions. In an acidic medium, the chromium is present in the dichromate ion (Cr\(_2\)O\(_7\)\(^{2-}\)), where it has an oxidation state of +6. This ion gives the solution its characteristic orange colour. When it acts as an oxidizing agent, it accepts electrons and is reduced to chromium(III) ions (Cr\(^{3+}\)), where the oxidation state is +3. The formation of Cr\(^{3+}\) ions (often as chromium(III) sulfate in sulphuric acid solutions) turns the solution green.

While standard chemical definitions usually limit metalloids to a list of six elements (Boron, Silicon, Germanium, Arsenic, Antimony, and Tellurium), Selenium is frequently classified as a metalloid in various educational contexts and standardized tests because it exhibits intermediate properties between metals and nonmetals. Though more strictly defined as a nonmetal in some academic circles, it is the only viable answer among the choices provided that displays "metalloid-like" or semiconducting behavior.

Iodine can be separated from calcium chloride using sublimation because of the distinct physical properties of the two substances: 1. Iodine is a sublimable solid, meaning it transitions directly from a solid state to a gaseous state upon heating without passing through a liquid phase. 2. Calcium chloride is a non-sublimable ionic salt with a very high melting point, so it remains in the solid state while the iodine vapourizes.

Sodium chloride (common salt) is a versatile chemical used in various industrial and domestic processes. While it has many applications, it is not typically used for the primary treatment of water (such as purification or filtration of polluted water).

A metallic bond is an intramolecular (chemical) bond rather than an intermolecular force. It involves a lattice of metal cations surrounded by a "sea" of delocalized valence electrons. Because this bond exists within a substance to hold its atoms together rather than between discrete molecules, it does not qualify as an intermolecular force.