Physics Chapter 1: Effects Of Electric Current Quiz

Tungsten is used for making filament because it has a high melting point, good electrical conductivity, and low vapor pressure. These properties make it suitable for use in incandescent light bulbs, where the filament needs to be heated to high temperatures without melting or evaporating. Copper, nichrome, and aluminium do not possess the necessary properties for filament production, making tungsten the correct choice.

The unit of power is watt. Power is defined as the rate at which work is done or energy is transferred. It is measured in watts, which are derived from the joule per second. One watt is equal to one joule of energy transferred per second. Therefore, watt is the correct unit of power.

The heat sink is the part used for absorbing the heat produced in an LED bulb. LED bulbs generate heat during operation, and the heat sink helps to dissipate this heat, preventing the bulb from overheating. It is typically made of a thermally conductive material, such as aluminum or copper, which helps to transfer the heat away from the LED components and into the surrounding environment. By efficiently dissipating heat, the heat sink helps to prolong the lifespan and maintain the performance of the LED bulb.

When two resistors are connected in series, the effective resistance increases. This is because in a series circuit, the total resistance is equal to the sum of the individual resistances. As the current passes through each resistor in series, it encounters more resistance, resulting in an overall increase in resistance. Therefore, when resistors are connected in series, the effective resistance increases.

When a storage battery is being charged, electrical energy is converted into chemical energy. This is because the charging process involves the movement of electrons, which causes a chemical reaction to occur within the battery. This chemical reaction stores energy in the form of chemical potential energy, which can later be converted back into electrical energy when the battery is discharged. Therefore, the correct answer is "Electrical energy to Chemical energy."

Nichrome is an alloy that is commonly used as a heating element in electrical appliances due to its high resistance to heat and corrosion. It is composed of nickel, chromium, and iron. Nickel provides strength and ductility to the alloy, chromium enhances its resistance to oxidation and corrosion, and iron acts as a stabilizing element. Therefore, the correct answer is Nickel, Chromium, Iron.

To find the lowest resistance when combining resistors in parallel, we use the formula 1/R_total = 1/R1 + 1/R2 + ... + 1/Rn. In this case, we have 10 resistors with a resistance of 1 ohm each. Plugging in the values, we get 1/R_total = 1/1 + 1/1 + ... + 1/1. Simplifying the equation, we get 1/R_total = 10/1. Taking the reciprocal of both sides, we find that R_total = 1/10 ohm. Therefore, the lowest resistance that can be obtained by combining these 10 resistors is 1/10 ohm.

Tin and Lead are the materials used for making fuse wire. Fuse wire is designed to melt and break the circuit when there is an excessive flow of current, protecting the electrical appliances from damage. Tin has a low melting point and is resistant to oxidation, making it suitable for fuse wire. Lead has a high electrical conductivity and is easily molded, allowing it to efficiently conduct the current and shape into a thin wire. Together, Tin and Lead provide the necessary properties for an effective fuse wire.

LED stands for Light Emitting Diode. It is not a discharge lamp because it does not rely on the discharge of electricity through a gas or vapor to produce light. Instead, LEDs produce light through a process called electroluminescence, where light is emitted from a semiconductor material when an electric current passes through it. LEDs are known for their energy efficiency, long lifespan, and compact size, making them a popular choice for various lighting applications.

The bulb with the lower wattage will glow with more brightness in this scenario. This is because when bulbs are connected in series, the total voltage is divided among them. Therefore, the 30W bulb will receive a higher proportion of the total voltage compared to the 60W and 100W bulbs. As a result, it will glow with more brightness.