Ani is scuba diving. She descends 5 feet below sea level. She descends same distance 4 more times. What is Ani's final elevation?

A submarine was situated 450 feet below sea level. If it descends 300 feet. What is its new position?

A submarine was situated at 650 feet below the sea level. If it descends 200 feet, what is its new position?

Answer the following questions . a. The earth's magnetic field varies from point is space. Does it also change with time ? It so , on what time scate does it change appreciably ? b. The earth's core is known to contain iron. Yet geologists do not regard this as a source of the earth's magnetism why ? c. The charged currents in the outer conducting regions of the earth's core are thought to be responsible for earth's magnetism . What might be the ' battery ' (i.e., the source of energy) to sustain these currents ? d. The earth may have even reversed the direction of its field several times during its history of 4 to 5 billion years. How can geologists know about the earth's field in such distant past ? e. The earth's field departs from its dipole substantially at large distances (greater than about 30,000 km) what agencies may be responsible for this distortion ? f. Interstellar space has an extremely weak magnetic field of the order of 10^(-12) T, Can such a weak field be of any significant consequence ? Explain. [Note : Exercise 2 is meant mainly to arouse your curiosity . Answers to some question above are tentative or unknown . Brief answers wherever possible are given at the end . For details , you should consult a good text on geomagnetism.]

When the sun is directly overhead, the surface of the earth receives 1.4 xx (10^3) W (m^-2) of sunlight. Assume that the light is monochromatic with average wavelength 500mn and that no light is absorbed in between the sun and the earth's surface. The distance between the sun and the earth is 1.5 xx (10^11) m. (a) Calculate the number of photons falling per second on each square metre of earth's surface directly below the sun. (b) How many photons are there in each cubic metre near the earth's surface at any instant? (c) How many photons does the sun emit per second?

A cube of iron (density = 8000kg m^(-1) , specific heat capacity = 470g J kg^(-1)K^(-1) ) is heated to a high temperature and is placed on a larger block of ice at 0^(@)C . The cube melts the ice below it, displaces the water and sinks in the final equilibrium position its upper surface is just inside the ice. Calculate the initial temperature of the cube. Neglect any loss of heat outside the ice and the cube .The density of ice = 900 kg m^(-1) and the latent heat of fusion of ice = 3.36 xx 10^(5)J kg^(-1)

An ideal monatonic gas is confined in a cylinder by a spring-loaded piston of cross section 8.0xx10^(-3) m^(2). initially the gas is at 300K and occupies a volume of 2.4xx10^(-3)m^(-3) and the sprinng is in its relaxed state. The gas is heated by a small heater until the piston moves out slowly by 0.1m. Calculate the final tempreture of the gas. The force constant if the spring is 8000Nm^(-1) ,and the atmospheric pressure is 1.0xx10^(5)Nm^(-2) . the cylinder and the piston are thermally insulated. The piston and the spring are massless and there is no friction between the piston and the cylinder. Neglect any heat-loss through the lead wires of the heater. The heat capacity of the heater coil is negligible. assume the spring to be massless

In a musical chair game, the person playing the music has been advised to stop playing the music at any time within 2 minutes after she starts playing. What is the probability that the music will stop within the first half-minute after starting?

Find the number of positive integers, which can be formed by using any number of digits from 0, 1, 2, 3, 4, 5 but using each digit not more than once in each number. How many of these integers are greater than 3000? What happened when repetition is allowed?

Two insulated identically sized charged copper spheres A and B have their centers separated by a distance of 50 cm. q= 6.5 xx 10^(-7)C . A third sphere of the same size but uncharged is brought in contact with the first, then brought in contact with the second, and finally removed from both. What is the new force of repulsion between A and B?