All questions of June Week 3 for NEET Exam

Therefore resistance increases with the length. When cross sectional area increases the space of the elctrons to travel increases(simply explained). Therefore less amount of obstacles for the current. Therefore when area increases the resistance decreases.

The resistance increases as the temperature of a metallic conductor increase, so the resistance is directly proportional to the temperature. When we increase the temperature the amplitude of vibration of atoms increases as a result of which the number of collision among the electrons and atom increases, and hence resistances increases.

• Green: 5
• Red: 2
• Orange: Multiplier of 10^3 (1,000)

1. First digit: Green = 5
2. Second digit: Red = 2
3. Multiplier: Orange = 10^3 (1,000)

Electric heater is device to heat water.... So when it have high melting pt. it we sustain heat nd won't melt....nd resistance means to oppose heat... So it should have high resistivity to heat water without getting damage....HOPE THIS WILL HELP YOU....!

Temperature Coefficient of Resistivity

The temperature coefficient of resistivity is defined as the change in the electrical resistance of a material per unit change in temperature. It is denoted by the symbol α and has units of inverse temperature (K^-1) or reciprocal temperature (1/T).

Effect of Temperature on Electrical Resistance

When the temperature of a conductor increases, its electrical resistance also increases. This is due to the fact that as the temperature increases, the atoms in the conductor vibrate more vigorously, which results in more collisions between the electrons and the atoms. This increase in collisions leads to an increase in the resistance of the conductor.

Formula for Temperature Coefficient of Resistivity

The temperature coefficient of resistivity is given by the formula:

α = (1/ρ) x (dρ/dT)

where ρ is the resistivity of the material and dρ/dT is the rate of change of the resistivity with temperature.

Dimension of Temperature Coefficient of Resistivity

The dimension of the temperature coefficient of resistivity is the same as that of reciprocal temperature or (temperature)^-1. This can be seen from the formula for the temperature coefficient of resistivity:

α = (1/ρ) x (dρ/dT)

where ρ has units of ohm-meters (Ω.m) and dρ/dT has units of ohm-meters per Kelvin (Ω.m/K). Thus, the units of α are K^-1 or 1/T.

Conclusion

In conclusion, the temperature coefficient of resistivity is a measure of how the electrical resistance of a material changes with temperature. It has units of inverse temperature or reciprocal temperature, and its dimension is the same as that of (temperature)^-1.

The wire material has a high resistivity, and is usually made of an alloy such as Nickel-chromium (Nichrome) or a copper-nickel-manganese alloy called Manganin. Common core materials include ceramic, plastic and glass. Wire wound resistors are the oldest type of resistors that are still manufactured today.

The F1 generation from crossing a pure line round-seeded pea plant with a wrinkled-seeded pea plant will be round-seeded. This can be explained by the Law of Dominance, where round seeds are dominant over wrinkled seeds.

I apologize, but your question about the reaction is incomplete. Could you provide more information or detail about the reaction you are referring to?

Semiconductor - A material that is neither a good conductor of electricity nor a good insulator, but has properties of electrical conductivity somewhere between the two. Silicon and germanium are good semiconductor materials.

For 2nd graph half live is cons.on increasing conc.so it is of 1st order
for 1st graph rate remains cons.with time means independent on conc.so it is of 0 order
so ans.is c

Drift velocity of charge carriers in a conductor depend upon two factors, one is the intensity of applied electric field across the conductor and other is one property of the conductor called Mobility of Charge Carrier. In other words, for applied same electric field, on different metallic conductors there will be different drift velocities of electrons. These drift velocities of electrons depend upon a typical property of conductor called mobility of charge carrier.

The correct answer is option 'B', Emasculation.

Emasculation refers to the process of removing the anthers from a flower to prevent self-pollination and facilitate controlled cross-pollination. This technique is commonly used in plant breeding programs to produce hybrid plants with desired traits.

Here is a detailed explanation of the process of emasculation:

1. Purpose of Emasculation:
- Emasculation is performed to prevent self-pollination, where the pollen from the anthers of the same flower or plant is transferred to the stigma, leading to the production of self-pollinated seeds.
- By removing the anthers, the flower can be protected from self-pollination and allow for controlled pollination to introduce pollen from a different plant with desired traits.

2. Tools Required:
- Sterilized forceps or tweezers: These are used to carefully pluck the anthers from the flower without damaging the stigma or other reproductive structures.
- Sterilized scalpel or razor blade: This may be required to make precise cuts or remove unwanted parts of the flower during the emasculation process.

3. Procedure:
- Choose flowers that are at the right stage of development for emasculation. The flowers should be at the stage where the anthers are mature and ready to release pollen but the stigma is not receptive yet.
- Carefully remove the petals and sepals to expose the reproductive structures of the flower.
- Use sterilized forceps or tweezers to gently remove the anthers. Be cautious not to damage the stigma or other important parts of the flower.
- After emasculation, it is important to discard the removed anthers properly to prevent accidental pollination.
- It is also important to ensure that the stigma is not damaged during the emasculation process as it is the receptive part of the flower where pollen will be introduced later.

4. Importance of Emasculation:
- Emasculation is crucial in plant breeding programs to produce hybrid plants with desirable traits. By preventing self-pollination, breeders can control the pollination process and introduce pollen from a different plant to achieve specific genetic combinations.
- This technique allows breeders to create plants with improved characteristics such as disease resistance, increased yield, or better quality.

In conclusion, emasculation is the process of removing the anthers from a flower to prevent self-pollination and facilitate controlled cross-pollination. It is an important technique used in plant breeding programs to produce hybrid plants with desired traits.

I am in standard 11 not 12

Mendel's Law of Dominance states that in a pair of alleles, one may mask the expression of the other. The third option (C) cannot be explained by this law because the Law of Dominance does not address the concept of blending or recovery of both characters in the F2 generation. Instead, it focuses on how dominant traits mask recessive traits, and the characters appear as distinct and separate in the F2 generation.


give the remaining questions
ChatGPT

In basic terminology, the F1 generation is the first generation of offspring produced by a set of parents. The 'F' in F1 stands for 'filial.

If F2 dwarf plants (genotype tt) are self-pollinated, all the offspring (F3 and F4) will also be dwarf with the genotype tt.

Answer is (d) because the direction that positive test charges are pushed. Thus, these negatively charged electrons move in the direction opposite the electric field.

Mendel’s work was rediscovered in 1900 by De Vries, Correns, and von Tschermak. They independently found Mendel’s principles of inheritance, which had been overlooked and forgotten after their original publication.