FreeNotes
Statements: 1. A radioactive substance has a half-life of eight months. In how much time will three-fourths of the substance decay? 2. In 420 days, the activity of a sample of polonium (Po) decreases to one-eighth of its initial value. What is the half-life of polonium? 3. The half-life of radium is about 1600 years. … Read more
Statements: 1. What is the magnitude of force on a current-carrying conductor of length 25 cm carrying a current of 2 mA placed perpendicularly in a uniform magnetic field of 5 mT? 2. What is the magnitude of magnetic field strength in which a 15 cm conductor carrying a current of 5 mA experiences a … Read more
Statements: 1. A 12V potential difference is applied across a copper conductor with a resistance of 6 kilo-ohm. Find: The current passing through it. The charge passing through any cross-sectional area in one hour. 2. During lightning, a current of 15,000A is established when 40C charge passes through a tree due to a potential difference … Read more
Statements: 1. How many electrons are removed from a metallic sphere to get a charge of 100 pC? 2. Two point charges of 1.2 pC and 2.5 pC are separated by a 50 cm distance. Find the magnitude of the force between the two point charges. 3. The force of repulsion between two identical point … Read more
Statements: 1. A concave mirror has a radius of curvature of 15 cm. A small boy of height 90 cm is standing in front of it at 10 cm. Find the location, nature, magnification, and height of the image. 2. A 5 cm tall lighted candle is placed 12 cm from a convex mirror of … Read more
Statements: 1. In a busy street, traffic noise has an intensity of 10⁻² W/m². Find the intensity level in decibels. 2. A mosquito buzzing has an intensity level of 40 dB. Calculate the intensity of this buzzing sound. 3. What is the intensity level of the threshold of hearing and the threshold of pain? 4. … Read more